Rough idle, loss of power. Water in gas line?

It’s been unseasonably hot here lately, and I’ve been using the AC more and more in my 98 Ranger. Today, the idle was very rough and it feels like I have very little power in it anymore. Could I somehow have gotten water in the line? My last fuel fill was Saturday.

The check engine light has been on for about a month, but whenever the dealer checks it, he can’t see anything. Until today, there were no symptoms of anything being amiss.

engineer_comp_geek was suffering similar symptoms about a month ago on his Dodge Dakota. He picked up a new EGR valve, and after we put that in, he was good to go. What does the set code mean? Some sensor or device is out of range-which is it?

I neglected to mention that his catalytic converter had become clogged, which led to the destruction of the EGR transponder.

I was with you until EGR valve. :confused: Set Code? :confused: Transponder? :confused:

Man, the Ranger is a pickup truck, not a spaceship. :smiley: I have no idea what any of this is. I’m not very mechanically inclined. I can do basic service, that’s about it. I don’t know what any of the stuff means when he “hooks it up to the computer”, other than he told me once that a plug wire was loose. I didn’t seem to notice that this time. Everything seemed snug.

Water in the line seems unlikely to me, but it’s an easy problem to fix - just pour a bottle of rubbing alcohol into a full tank of gas. The alcohol will allow the water to mix with the gas and flow through the system.

A little water in the gas line causes fuel starvation. The engine uses the least amount of fuel at idle, so if there’s enough water to make it idle rough, I would expect it to have no power at all (i.e. you might not be able to even drive the truck). What’s more, the check engine light has been on for a month prior to the rough idle and lack of power.

Modern cars and trucks have lots of sensors (transponders) monitored by a computer. When the computer detects that one or more signals from the sensors isn’t what it should be, the check engine light comes on. The mechanic has a diagnostic device he can plug into the car which reads a set code from the computer telling which sensor is acting up. Often this leads directly to a part that should be replaced, like the Exhaust Gas Recirculation valve (EGR valve).

Take the truck back to the dealer. Now that it’s acting up, it should be easier to diagnose the problem. If the dealer can’t fix it now, he’s not trying. In that case, take it to a competent mechanic who wants your business.

Last time my car(92 accord) idled rough it was because one of my spark plugs went bad. I can’t attest to loss of power though, since I didn’t attempt to drive it. I suspect if did drive the car that there would be signfiicant loss of power. For the record my check engine light didn’t come on, but my car is ghetto and I wouldn’t be surprised if it had a bad sensor or two.

FWIW, my Ford car recently suffered the same symptoms – rough idle and loss of power. It just needed a new fuel filter.

The dealer isn’t open until Monday. Actually, the mechanic isn’t in until Monday. Maybe I’ll just shoot up Pep Boys tomorrow.

The check engine light isn’t really bothering me. The fact that the rough idle started seemingly overnight is.

Thanks, Jeff, for the simplified explanation. I know from past experience that danceswithcats was trying to be helpful, and he always is. It was all just Greek to me in this case.

Sorry to befunkle you. Stop by your local Auto Zone or similar. They will often read your diagnostic computer output free of charge and tell you what the code means, in the hopes of selling you repair part x.

Have you ever had the catalytic converter replaced? Although the overnight notation you just made reduces that on my index of probability.

It could be a number of things-let’s start with the code. :smiley:

Hit Auto Zone on the way home, and just like you suspected, the code for a bad EGR valve hit. The guy there said that before I go ahead and change it out ($50+ part that may not even need changing), I should try a few things. First, he said dump some “Emission Pass” or something into the gas tank. It’s supposed to take away some of the carbon. Tomorrow, I’m going to take of the EGR valve (he showed me where it was and how to remove it) off and clean out the pipes with a wire brush. Third, he said if it continues after those have been done, try changing the gas cap. Last resort is to change the valve itself.

Looks like an easy enough job, I think I’m up for it. If not, then my brother in law will do it.

At least the check engine light went out for a half an hour. :smiley:

Thanks for pointing me in the right direction.

Good ole mechanic in a can. Sure, why rebuild an engine that is pumping oil and smokes like a bitch, when you can add motor honey.

This actually is a good, and valid suggestion. When you have the valve off, check to see if it is seating completly, a rough idle coupled with an EGR code tells me that the valve is leaking exhaust gas at idle.

This qualifies as the funniest thing I have read about auto repair in at least a month. Let me get this right, you have a check engine light with a code that points to EGR system. You have driveability issues which can occur with EGR issues and this wingnut is trying to sell you a gas cap? :eek: :dubious:
Sure gas caps can set check engine lights, but the associated code is for a leak in the evap system, not the EGR system. Furthermore, there will be no idle or driveability issues from a bad gas cap. Hell changing the gas cap will have about the same effect on your rough idle as changing the air in your tires from Winter air to summer air. (you have rotated the air in your tires haven’t you? You haven’t? Great I some special no Ozone air right here, it’s only $29.95 per tire) :smiley:

I’m a little worried about your lack of power.

As danceswithcats said, my problem was that a clogged exhaust caused the EGR unit to fail. Once I fixed the exhaust clog (my catalytic converter had come apart inside), I had plenty of power, I just had a rough idle from the EGR system being messed up.

Check your muffler and catalytic converter. One of them might be the real culprit.

Two burned plug wires.

One was completely burned, causing a miss, so I was driving on 5 cylinders. The second one was burned, but still working. Close to not working, though. They heard the arc as soon as they popped the hood. Not knowing enough to know what that noise was, I didn’t hear it, I guess. Apparently, before I bought the car, the last guy to do work on the plugs never snapped the wire into the harness, so they were free to flop around and melt against the engine.

Guys changed all the wires, plugs, ran diagnostic, cleared codes, and the truck is back to running like a champ. All for the low, low price of…well, probably more than I should have paid. :rolleyes:

Thanks again, fellas.

Don’t use rubbing alcohol; it already is saturated with as much water as it can hold.

Use an isopropyl based drygas, not one based on methanol: with methanol, you end up with an alcohol/water layer, and an alcohol/gasoline layer. Straight isopropil/water/gasoline mixes into a homogenous single layer.