Car stalls out because of random misfire and evap system running too lean

Hi, I have a 2001 Chevy Prizm with 116,500 miles (aprox) on it. When I start my car after not being in use for a few hours the engine will run rough and then stall out. Then when I start it again immediately after the engine stalls it will for the most part run smooth. Also, the check engine light indicator on my dash is on.

I took it to a Goodyear garage yesterday (04/28/09) to get checked out. The mechanics ran a engine diagnostic circuit test. I wast told by the mechanics that they reset the codes, but that it would not guarantee the car’s engine from stalling out again. They also told me from the diagnostic test that it is more then likely it is random misfire and there is problem somewhere along the evap system, which is running too lean. The owner of the Goodyear place said he does not have the equipment to repair my car and that I should take it to a Chevy dealer.

Does this sound correct to you? If so, does it sound like a easy problem to fix? About how much can I expect to pay for this to be repaired?

Any advice or opinions on this matter will be greatly appreciated. Thanks advance. :slight_smile:

It sounds like nonsense. You need to post the actual codes. There is no code for “evap system, which is running too lean.” The evap system doesn’t run lean or rich.

I suggest you take your Prizm to an independent mechanic. You don’t need a Chevy dealer, and you don’t need to pay dealer prices. If you don’t have a regular mechanic now’s a good time to establish a relationship with one.

Any decent mechanic can diagnose and correct whatever problems your car has. Goodyear is a tire store. You need a mechanic, not a tire shop.

Have you been following the recommended maintenance schedule? My guess is, no, you haven’t, and your car now needs to be brought up to date.

It’s impossible to estimate repair costs until you know exactly what’s wrong.

You might save yourself a lot of money if you did the routine tune-up type of stuff on the car: fuel filter, air filter, spark plugs, spark plug wires, pcv valve. If there is still a problem, a “fuel system cleaning” and an “intake tract cleaning” are legitimate services to have performed.
None of these things are sworn to fix the problem; but, shouldn’t you feel foolish if, after lots of money spent on parts, it came back to the types of things I named?

Get your fuel pressure tested. Could be the pump or check valve going.

mcparadise, I appreciate the suggestions. As for following the maintenance schedule I followed that religiously. I can definitely rule out this problem being caused by not maintaining my vehicle.

hellokit, thanks for the suggestions.

I agree with McP’s suggestion of bringing this to a reputable independent garage. You don’t need a dealership for this type of problem.

Just for informational purposes, the EVAP (evaporative emissions) system is simply the system that contains gas (hydrocarbon) fumes that would otherwise evaporate from your gas tank into the air. They’re captured in a charcoal (containing) canister under the hood and then allowed to be ingested into the engine to be burned. The EVAP system doesn’t run lean or rich, it’s just a recovery system for evaporating gas fumes. I suspect you may have misunderstood the Goodyear guy.

The gas tank also breaths in through this canister as the gas is pumped out, and it is possible that the EVAP system is plugged by a kinked line or saturated charcoal bed and the tank is developing a vacuum preventing the pump from maintaining fuel pressure, but let the tech check the codes and do the diagnosis.

Kudos to the Goodyear shop for referring you elsewhere when they recognized that they were unprepared to proceed with this repair. We get way too many posts about shops that can’t do the work and simply throw parts at the problem at the customer’s expense.

Since it only has this problem after sitting for a few hours, or overnight, maybe it’s losing fuel pressure at rest.
The fuel system should maintain residual fuel pressure which allows the car to start instantly and run fine.
If the system is losing pressure (leaking injector, fuel pressure regulator, or fuel pump check valve) then the rough running can be caused by the air bleeding out of the system after startup. The pump check valve is the normal culprit.

A rough running engine due to the air bleeding out can set a random misfire code and the CEL.

Without actually starting the engine, the next time you go to start the car after it’s been sitting for a while try turning the key on and off at least half a dozen times; allowing the key to stay in the RUN position for at least a couple of seconds each time.
Then try to start the car. If it starts and runs fine then you know it’s a fuel pressure loss problem more than likely.

This could also be verified with a simple fuel pressure test.

No surprise that the Goodyear or any other mechanic has no clue. If I were as strong as a normal person I could get a job as a mechanic without a real clue. The employers want warm bodies more than really qualified ones. The answer is yes, this sounds correct to me.

It also sounds true that he does not have the equipment (manual with some troubleshooting instructions). You will probably get better results from a dealer if you don’t have a good shop near you. Your codes are looking like “not much help” but a little experienced help might get you somewhere. A random misfire can be caused by quite a list of things.