# Mechanically inclined Dopers.... What's wrong with my car?? **URL:** \ **Category:** Factual Questions\ **Created:** [June 10, 2003, 1:15pm UTC](https://boards.straightdope.com/t/mechanically-inclined-dopers-whats-wrong-with-my-car/180847 "2003-06-10T13:15:06Z")\ **Posts on this page:** 18\ **Page:** 1
**Author:** ![NoGoodNamesLeft](https://avatars.discourse-cdn.com/v4/letter/n/8797f3/32.png) [@NoGoodNamesLeft](https://boards.straightdope.com/u/NoGoodNamesLeft)\ **Post date:** [June 10, 2003, 1:15pm UTC](https://boards.straightdope.com/t/mechanically-inclined-dopers-whats-wrong-with-my-car/180847/1 "2003-06-10T13:15:06Z")
I have a 1995 Ford Escort. Recently, it’s started sputtering on acceleration and at very low speed/idle. (Forward & reverse, not so much in Neutral). It feels as though the whole car shakes (almost violently) when it does this. It’s stalled once or twice at a stoplight. I’m thinking fuel delivery. I don’t smell fuel or drip when parked, so I don’t anticipate a leak. Maybe the fuel pump? My mechanic said he’ll check wiring as well, but I had the wiring replaced not too long ago. Could they have worn this fast? Spark plugs don’t fire when driving, do they? I’m really not thinking Transmission. This is happening in all gears (auto) and forward / reverse. I’ve blown a tranny before…it felt like I was trying to drive through peanut butter. It doesn’t feel like that at all. Anybody else have any ideas? Also, what can I expect to pay for a Fuel Pump? ---
**Author:** ![handy](https://avatars.discourse-cdn.com/v4/letter/h/b5a626/32.png) [@handy](https://boards.straightdope.com/u/handy)\ **Post date:** [June 10, 2003, 1:56pm UTC](https://boards.straightdope.com/t/mechanically-inclined-dopers-whats-wrong-with-my-car/180847/2 "2003-06-10T13:56:36Z")
I’d say a Fuel filter. You change them about every 20,000 miles. ---
**Author:** ![NurseCarmen](https://avatars.discourse-cdn.com/v4/letter/n/5daacb/32.png) [@NurseCarmen](https://boards.straightdope.com/u/NurseCarmen)\ **Post date:** [June 10, 2003, 2:08pm UTC](https://boards.straightdope.com/t/mechanically-inclined-dopers-whats-wrong-with-my-car/180847/3 "2003-06-10T14:08:47Z")
Spark plugs do fire when driving. nuther vote for fuel filter here. ---
**Author:** ![Uncommon\_Sense](https://avatars.discourse-cdn.com/v4/letter/u/f9ae1b/32.png) [@Uncommon\_Sense](https://boards.straightdope.com/u/Uncommon_Sense)\ **Post date:** [June 10, 2003, 2:15pm UTC](https://boards.straightdope.com/t/mechanically-inclined-dopers-whats-wrong-with-my-car/180847/4 "2003-06-10T14:15:41Z")
> [@](#): > > \*Originally posted by NoGoodNamesLeft \* > \*\*I have a 1995 Ford Escort. Recently, it’s started sputtering on acceleration and at very low speed/idle. (Forward & reverse, not so much in Neutral). It feels as though the whole car shakes (almost violently) when it does this. It’s stalled once or twice at a stoplight. > > Anybody else have any ideas? Also, what can I expect to pay for a Fuel Pump? \*\* Probably about as much as the car is worth. --JK. Could be a vacuum leak too. Check the small black tubes (hoses) that run throuhout the engine compartment, one of them could be broken, cracked or disconnected. Usually a fuel delivery problem would prevent you from going fast or accelerating, not idling. ---
**Author:** ![Scylla](https://avatars.discourse-cdn.com/v4/letter/s/a5b964/32.png) [@Scylla](https://boards.straightdope.com/u/Scylla)\ **Post date:** [June 10, 2003, 3:05pm UTC](https://boards.straightdope.com/t/mechanically-inclined-dopers-whats-wrong-with-my-car/180847/5 "2003-06-10T15:05:08Z")
Your problem is pretty general, and could be any of a number of things. You want to nail it down by troubleshooting before you start replacing parts. Since you don’t know how to do this, you need a mechanic. It could be anything from a dirty air filter, gas filter, to your timing, your wires, your plugs, your computer, your sensors, etc. ---
**Author:** ![Gary\_T](https://avatars.discourse-cdn.com/v4/letter/g/3ec8ea/32.png) [@Gary\_T](https://boards.straightdope.com/u/Gary_T)\ **Post date:** [June 10, 2003, 3:31pm UTC](https://boards.straightdope.com/t/mechanically-inclined-dopers-whats-wrong-with-my-car/180847/6 "2003-06-10T15:31:36Z")
_My mechanic said he’ll check wiring as well, but I had the wiring replaced not too long ago._ What does this mean? “Wiring” generally refers to the complex of wires that connect various devices electrically. There are hundreds of different electrical circuits, and miles of wire. “Check wiring” and having the “wiring replaced” sound terribly vague and broad. Now, in the case that he said he’d check the spark plug wires, that certainly makes sense for the symptom described. However, if the plug wires were replaced recently it would be very unusual for them to be faulty. Fuel filters are often overlooked maintenanence items, and when they start getting plugged they will affect performance. But sputtering and/or dying at idle is not a typical symptom of a fuel filter problem. For your car, the fuel filter replacement interval is probably 60,000 miles. The fuel pump is a possibility. Appropriate testing will show whether it’s working properly or not. Replacement (not including testing) is likely to run in the 150-200 range. Vacuum leaks typically do affect idle quality, but very seldom affect acceleration. The most likely general suspects for the symptoms described are spark plugs, plug wires, distributor cap and rotor, and certain key sensors. We can guess all day along about what it might be, but testing the car is the only way to know. ---
**Author:** ![NoGoodNamesLeft](https://avatars.discourse-cdn.com/v4/letter/n/8797f3/32.png) [@NoGoodNamesLeft](https://boards.straightdope.com/u/NoGoodNamesLeft)\ **Post date:** [June 10, 2003, 4:20pm UTC](https://boards.straightdope.com/t/mechanically-inclined-dopers-whats-wrong-with-my-car/180847/7 "2003-06-10T16:20:39Z")
I had the ignition wiring & the Spark Plug wiring replaced about a year or so ago. There is no electrical interruption (ie lights, radio -except when stalled) so I assumed we’d be looking at ignition wiring or spark plug wiring. Then again, IANAMechanic, which is why I asked for general advice on a message forum. What would a fuel filter problem behave like if not sputtering? I’d think if fuel was unable to clear the filter fluidly, it would result in intermittently lower volumes of fuel getting to the engine, hence sputtering. Is this not close?? I wasn’t terribly clear in my OP, but I am going to my mechanic tomorrow, I just wanted ot see if anyone else had a similar problem and hopefully rule out a problematic part in the model. whuckfistle, I’m not unable to idle, but when I come to a stop (stoplight for example) it stalled (only twice, not eveytime). That lead me to look at fuel delivery because it seemed that the problems seem to happen when A) There is little/no fuel being delivered to the engine (hence any disruption would threaten to cut off the engine) and B) when accelerating (So, when I try to apply fuel to the engine, it doesn’t seem to be taking it all that well.) There is no problem associated with gear changes, so I’m fairly certain I can rule out Transmission. I’m wondering about Spark Plugs now though, after reading some of these posts. Thanks guys! I guess I’ll have to wait & see how close to right I was. ---
**Author:** ![Gary\_T](https://avatars.discourse-cdn.com/v4/letter/g/3ec8ea/32.png) [@Gary\_T](https://boards.straightdope.com/u/Gary_T)\ **Post date:** [June 10, 2003, 4:43pm UTC](https://boards.straightdope.com/t/mechanically-inclined-dopers-whats-wrong-with-my-car/180847/8 "2003-06-10T16:43:13Z")
_What would a fuel filter problem behave like if not sputtering? I’d think if fuel was unable to clear the filter fluidly, it would result in intermittently lower volumes of fuel getting to the engine, hence sputtering. Is this not close??_ Sputtering/cutting out/bogging down while **accelerating** is a typical symptom of a restricted fuel filter (it’s not from intermittent lack of fuel but from inability do deliver sufficient volume). Sputtering–or any symptom, including dying/stalling–while **idling** is not typical of a fuel restriction. That’s when there’s the least demand for fuel. For a filter to be restricted enough to affect idling, it would have already caused a virtual inability to accelerate at all and difficulty starting the engine. ---
**Author:** ![Necros](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/necros/32/11086_2.png) [@Necros](https://boards.straightdope.com/u/Necros)\ **Post date:** [June 10, 2003, 4:50pm UTC](https://boards.straightdope.com/t/mechanically-inclined-dopers-whats-wrong-with-my-car/180847/9 "2003-06-10T16:50:45Z")
I’m going with Gary on this one, and saying it’s an electrical issue (plugs, wires, distributor, maybe even a coil…) ---
**Author:** ![Uncommon\_Sense](https://avatars.discourse-cdn.com/v4/letter/u/f9ae1b/32.png) [@Uncommon\_Sense](https://boards.straightdope.com/u/Uncommon_Sense)\ **Post date:** [June 10, 2003, 4:58pm UTC](https://boards.straightdope.com/t/mechanically-inclined-dopers-whats-wrong-with-my-car/180847/10 "2003-06-10T16:58:28Z")
> [@](#): > > \*Originally posted by Gary T \* > \*\*_What would a fuel filter problem behave like if not sputtering? I’d think if fuel was unable to clear the filter fluidly, it would result in intermittently lower volumes of fuel getting to the engine, hence sputtering. Is this not close??_ > > Sputtering/cutting out/bogging down while **accelerating** is a typical symptom of a restricted fuel filter (it’s not from intermittent lack of fuel but from inability do deliver sufficient volume). Sputtering–or any symptom, including dying/stalling–while **idling** is not typical of a fuel restriction. That’s when there’s the least demand for fuel. For a filter to be restricted enough to affect idling, it would have already caused a virtual inability to accelerate at all and difficulty starting the engine. \*\* I Agree. My hunch is that it is either a weak spark or a vacuum leak. When the engine is at lower RPM`s the coil voltage can drop (if there is a problem) and effect the spark to the plugs. Also, the vacuum or emmision circuit problems can become pronounced at idle - whereas at higher RPM`s they may go away or become “hidden”. ---
**Author:** ![TBone2](https://avatars.discourse-cdn.com/v4/letter/t/6a8cbe/32.png) [@TBone2](https://boards.straightdope.com/u/TBone2)\ **Post date:** [June 11, 2003, 12:11am UTC](https://boards.straightdope.com/t/mechanically-inclined-dopers-whats-wrong-with-my-car/180847/11 "2003-06-11T00:11:54Z")
I have to go with **Gary T** and **whuckfistle** here. The company pickup I drive (2000 Chevy 2500) recently exhibited symptoms almost exactly like the OP described, and it turned out to be bad spark plug wires. As has been pointed out many times already, the symptoms don’t point toward the fuel delivery system, which works hardest (and is therefore most likely to fail) under severe loading, e.g. climbing a hill, towing a trailer, passing another vehicle, etc. Though it _could_ be vacuum or environmental stuff as suggested, I’d check the primary ignition components first. Modern electronic ignition systems regulate voltage independently, based on inputs from various sensors. (Unlike the simple old battery-coil-plugs “dumb” systems I grew up with.) So voltage to the spark plugs drops, not only at low-idle, but also in low-load situations, like cruising up the street at a relatively low RPM. My truck, for example, would cough and miss at low-idle, was harder than it should be to start, and wanted to stutter when a level grade cruising situation changed to a slight up-grade cruising situation. The engine was loaded somewhat more heavily, but the voltage didn’t increase enough to overcome the excessive resistance in the plug wires. Essentially, the fuel/air mixture was “drowning” the spark plugs. Good luck, but I highly recommend you buy yourself a real car. ---
**Author:** ![handy](https://avatars.discourse-cdn.com/v4/letter/h/b5a626/32.png) [@handy](https://boards.straightdope.com/u/handy)\ **Post date:** [June 11, 2003, 3:18pm UTC](https://boards.straightdope.com/t/mechanically-inclined-dopers-whats-wrong-with-my-car/180847/12 "2003-06-11T15:18:17Z")
"What would a fuel filter problem behave like if not sputtering? " Not much, but I have seen this a few times, a filter is pretty easy to put in anyway. ---
**Author:** ![iaboy12](https://avatars.discourse-cdn.com/v4/letter/i/ccd318/32.png) [@iaboy12](https://boards.straightdope.com/u/iaboy12)\ **Post date:** [June 13, 2003, 3:42am UTC](https://boards.straightdope.com/t/mechanically-inclined-dopers-whats-wrong-with-my-car/180847/13 "2003-06-13T03:42:38Z")
ok, i have a similar problem to what is being described. my car will often have problems starting and will have problems accelerating. the kicker is that it only does it when it is hot outside. when it is cool out it drives great. any ideas on this? oh, and i had another problem a few months back that took forever to figure out what it was. in that time i replaced the fuel filter, air filter, plugs and roter, catalytic converter, and finally the distributer (which was the problem). so it is none of those. oh yeah, it is an '86 plymouth reliant k (any BNL fans out there?). any help would be greatly appreciated. ---
**Author:** ![handy](https://avatars.discourse-cdn.com/v4/letter/h/b5a626/32.png) [@handy](https://boards.straightdope.com/u/handy)\ **Post date:** [June 13, 2003, 3:10pm UTC](https://boards.straightdope.com/t/mechanically-inclined-dopers-whats-wrong-with-my-car/180847/14 "2003-06-13T15:10:05Z")
With an mid-80s Renault you can push the gas pedal down & a code shows up that indicates what needs checking. Do you have such a trick on your car iaboy12? The Renault needed a map sensor. ---
**Author:** ![iaboy12](https://avatars.discourse-cdn.com/v4/letter/i/ccd318/32.png) [@iaboy12](https://boards.straightdope.com/u/iaboy12)\ **Post date:** [June 14, 2003, 3:56am UTC](https://boards.straightdope.com/t/mechanically-inclined-dopers-whats-wrong-with-my-car/180847/15 "2003-06-14T03:56:01Z")
i don’t think i do. where does the code show up? i’ve never heard of that. ---
**Author:** ![Blown\_Injected](https://avatars.discourse-cdn.com/v4/letter/b/a87d85/32.png) [@Blown\_Injected](https://boards.straightdope.com/u/Blown_Injected)\ **Post date:** [June 14, 2003, 5:04am UTC](https://boards.straightdope.com/t/mechanically-inclined-dopers-whats-wrong-with-my-car/180847/16 "2003-06-14T05:04:24Z")
Don’t know if your car has a MAF sensor, if it does then check that, also maybe EGR. ---
**Author:** ![handy](https://avatars.discourse-cdn.com/v4/letter/h/b5a626/32.png) [@handy](https://boards.straightdope.com/u/handy)\ **Post date:** [June 14, 2003, 2:53pm UTC](https://boards.straightdope.com/t/mechanically-inclined-dopers-whats-wrong-with-my-car/180847/17 "2003-06-14T14:53:09Z")
“where does the code show up?” I wondered about that too, it was a relatives car, they must make a special box that displays the codes but maybe someone here can give us more info. ---
**Author:** ![Mr.Blue\_Sky](https://avatars.discourse-cdn.com/v4/letter/m/d26b3c/32.png) [@Mr.Blue\_Sky](https://boards.straightdope.com/u/Mr.Blue_Sky)\ **Post date:** [June 14, 2003, 3:25pm UTC](https://boards.straightdope.com/t/mechanically-inclined-dopers-whats-wrong-with-my-car/180847/18 "2003-06-14T15:25:06Z")
I have a 1994 Escort. I got the Haynes manual for it. It describes a method to get computer codes without buying expensive diagnostic tools. I did have a stalling-at-idle problem when I first got it (used). Turned out to be a vacuum leak.