So i just got a 2000 Chevy Cavalier and the guy said he ran it our of gas and it has not ran right since. We cleaned out the fuel tank and replaced the fuel pump. But it still misfired so we changed spark plugs wires and coil. Still nothing good so we used our code reader and its not throwing any codes I do not know what to do i need help please!!!
Considering everything you’ve replaced so far you might have a fuel injector problem. Running out of gas may have dislodged a particle of debris in the fuel line and clogged an injector. Is it a regular miss confined to one cylinder or is it random?
Is there a way to test that or do i just have to replace it And it only misfires when its in gear and its random
One thing you might try first is a can of Seafoam. I’ve never used it but the some of the guys here swear by it. As far as testing an injector there’s really no way a DIYer can do that if it’s a clogging problem.
we already tried sea foam and it didnt work
As long as i rev it on the throttle body it doesnt misfire but when im in the car it does
Is this a 2.2 or a 2.4 engine?
it is a 2.2
Most likely is a fuel system or ignition system problem of some kind. Less likely, but still possible, running out of gas can damage the cat. Is there a way you can temporarily bypass it to see if that improves things? That might provide a clue anyway.
i can try thank you
You won’t be able to disconnect your catalytic converter without cutting the pipe. It’s a welded one piece unit from the exhaust manifold to back behind the converter. The whole system is stainless steel. I have a 2001 Cavalier. The whole exhaust system is original.
One question - You said you replaced the coil. There are two coils. Did you replace them both?
One thing you might try. Check the fuel rail pressure. There is a test port on the fuel line about halfway back on the firewall side of the engine. It’s a schrader valve and should have a green plastic cap on it. You should see about 44 PSI.
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Without a misfire fault I have to wonder if you are simply dissatisfied with the idle quality of an old 4 cylinder car. If it is misfiring post the fault code, with the RPM and throttle angle when it occurs.
Sometimes you can get an indication of the cat by an intake manifold vacuum test. Ask your shop to measure the intake manifold vacuum at idle, then manually bump the rpm higher, say to 2000- 2500. Then back to idle. The manifold vacuum should become much less, close to zero as the throttle initially opens, then the vacuum should increase slowly with the throttle held open the same amount. When you then close the throttle back to the idle position the vacuum should go very high momentarily, then retreat to where it started. What happens when you do that on your Chevy?
An exhaust restriction will cause a performance problem (lack of power) that will be a greater concern than a rough idle. Fooling around with the exhaust system without a related symptom is a waste of time.
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