Rough idle, gas smell



Dealership “repaired” my car twice and I still have a rough idle, gas smell and check engine light. They first replaced a cracked hose, was fine for a few weeks. Then replaced a gas valve. Repairs so far $900…I still have the problem. It’s a 1998 w/ 164,000 miles and excellent maintenance-- needs new front brakes soon. I think it’s time for a new (er) car as job 2 young kids, etc don’t allow for luxurious afternoons spent at lexus dealership…not to mention it’s hard to leave the dealership without promising first born…husband disagrees on time for new car… Looking for ideas on problem or ideas on a new(er) car. I think husband might defer to Car Talk expertise.


The place to start would be letting the board know what code(s) have been associated with the check engine light. They are in the format P0123. Check you invoices as they may have been recorded. If not many auto parts chain stores will read them for free. If you do have the invoices handy also try to be more specific about what has been repaired/replaced.

You also don’t need a dealer. Most any reputable local mechanic can do the work and normally for a lot less.


Hi, thanks for the response…THe only think I saw with a 4-digit and a “P” with it was “STK: 2893P” Does taht mean anything? That is on the recent slip from the dealer…I have to dig out the other one.


Also, the second thing replaced was an EGR Valve. THe first was a cracked hose…same system…something about air in the gasoline? I’ll dig up the invoice and check on the first one.


My first suspect based on the symptoms would be a leaking fuel pressure regulator unless that is what you mean by a gas valve.


If it is a General Motors product, suspect the coil pack, aka “Distributorless Ignition System Module.” You can diagnose erratic spark with an inductive timing light. Light will flicker and have random periods when it’s off. Check on plug wires to every cylinder.

Misfire is random, so there is no dead cylinder code. But it will throw codes like crazy for ERG and O2 systems due to raw fuel in the exhaust. Since it’s random, there will be no fouled plugs to show you a “smoking gun.”