Coming to school my car began to sputter travelling along I-70. I pulled over, checked hoses, fluids, electrical, etc. and everything seemed good. I’m not sure how a car would act with water in the gas tank or with bad spark plugs, but I’m thinking it’s one or the other or both.
I only notice the problem when I’m accelerating (at any speed) but the jerking motion goes away once my speed is constant. For example, it took me about 45 seconds to get up to about 70mph due to all the sputtering (spuddering?) but once the car was cruising it was smooth as silk.
1993 Pontiac Grand Prix
3.1L
194K miles
p.s. - FWIW, I don’t think the plugs have been changed since around 150K, and i planned to change them at 200K.
I thought this was implied, but I guess not.
Any ideas what I can do here at school to ensure I get home without relying on public transportation? Is there water in the tank or what? How would I get the water out?
The symptoms you describe could be caused by a number of things. Worn spark plugs and water in the gas are two of the possibilities, but there are many others, some of which are more likely. Faulty ignition parts (plug wires, distributor cap if applicable, ignition module) and faulty fuel system parts (fuel filter, fuel pump) are at the top of the suspect list. Without doing some testing, there’s no way for us to know what’s causing the problem.
There are two ways to deal with this: start replacing parts until the problem is solved, or have it tested and repaired by a competent repair facility. Diagnosis by replacing parts can be efficient if your first or second guess is correct, but more often it’s a way to spend a lot of time and money without accomplishing much.
Hmmm. what does the manual say on changing spark plugs? Mine says every 30,000 miles but I would do them more often with that nbr of miles that you have.
edmunds.com usually has a forum for the car you have & there you can ask guys what they think who also own the same car. Find your car there & see if there is a forum.
YRMV, but you just described to a tee the time I had a bad fuel filter. It makes sense if you think about it. It can’t handle a sudden surge of fuel (i.e. when accelerating) but it is capable of allowing a limited flow (i.e. when cruising, or going slow)
Give that a good hard look first. I’m unfamiliar with your set up, but I hope your filter is easily accesible. Stop by the auto parts store and pick up a Haynes Manual. Those books pay for themselves.
I had an old Chevy Monte Carlo that had similar problems due to a vacuum leak (one of the hoses was bad and tended to pop off). This whacked out the vacuum advance on the distributer which royally screwed acceleration, but the car ran fine at constant speeds. I don’t know if a 93 grand prix is old enough to still have a vacuum advance distributer though.
Another thing to do is wait until it is dark and open the hood with the engine running, and give the engine a good squirt with a hose. If you see a big fireworks display then you need new spark plug wires.
I agree with the others that it could also be a fuel problem, either a clogged filter or maybe your fuel pump is going south. Or maybe its in the carb/tbi/fuel injectors (whatever your car has).
If you plan on keeping the car for a while I’d probably take the shotgun approach and replace the fuel filter, plugs, and wires, and see where that leaves you, because those are all things that probably are about due anyways.
I`ll go with fuel filter too. Cheapest to fix also.
I had a sputtering car and it turned out the alternator was going south. It could not provide the spark energy for excelleration but was OK at cruise. When it finally went everything ceased. Oh - lights got dimmer first then everything ceased.
Get the filter first then put some HEAT (name brand) in the tank to make sure no water is in there.
It won`t be the plugs only, but a bad spark or weak fuel supply could cause the plugs to foul.
I got it back to the shop after school and it turned out to be the fuel pump. It was only putting out 2PSI when it should have at least been putting out 6PSI. Everyting else was working good.