03 impala rought idel no ckeck engine light


Asked by Bernie329 Apr 15, 2022 at 11:45 AM about the 2003 Chevrolet Impala FWD

Question type: Maintenance & Repair

When I purchased it, it had been sitting for a while. On startup it would run rough and died some times. So I did a tune on and add fuel injector cleaner and the problem seem to go away. But now it is bogging at 3000 rpm, and there is no check engine light.

8 Answers


Scan for codes even if the light ain't on could be a pending code , the gas tank may need to be cleaned out with any luck there's an access plate in the trunk .

1 people found this helpful.

Hey man thanks for the Helpful answer!! Today I actually did a pressure test on the fuel pump by just turning the key on and hooking up a gauge. I got a reading of 55 psi which is good according to the web. So now I’m thinking it’s not the fuel pump. But maybe it could be dirty like you said I’ll see if I can look in there and see anything. Also when I called up a local dealer for parts they told me it could possibly be the ignition module. So not sure on that. But I do definitely want to get it scanned for codes somewhere now, just to see.


So it could be a fuel delivery problem, the exhaust is restricted or you have some sensors misreading. A live data scan would be the first thing to do.

1 people found this helpful.

OK, situation update, today I replace the ignition module and fuel pump and there was no change. It revs up perfectly in the driveway, but as soon as you try and go up a hill it barely can makes it. And there is still no type a check engine light, even though it hardly runs when driving. But will Idle perfectly. Just as a sidenote it does have 120,000 on it if that helps at all. I will get it scanned for Codes as soon as I can then.


Still get a live data scan. If that checks out then a exhaust system back pressure test.

1 people found this helpful.

Thanks everyone for the answers, had the cat replaced and everything is good now yeah:).

1 people found this helpful.

Great news. Yep too much exhaust system back pressure.


if the cat collapsed, it might be a good idea to change the thermostat.

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