My 97 Accord SE failed smog. The CO level was three times the max for California emmisions. Tech says it's running rich. Little background on car. Bought it last year on Craigslist. Check engine light was on. Took car to shop and mechanic said the ECU was kicking out codes for different car. Basically wrong ECU. Took a chance and bought correct ECU for $100. Installed 4 months ago and check engine light hasnt come on since. But car still having same issues since day I bought it. When it's idle it starts shaking like it's out of gas and ready to die. When I step on gas it hesitates like it's not getting any gas, then theres a popping noise from engine area and car will accelerate as if it finally got the gas it needed to get going. Did a full tuneup, changed fuel filter. My question is it possible the ECU I bought is not good? Should the check engine light be on for the problem my car is having?

 

I'm thinking fuel pressure regulator or possibly bad injector(s). Is it throwing any codes?

 

If your car is running rich, the number 1 reason is normally an exhaust leak.

However, if there's a popping sound coming from the engine, first thing you should check is the mechanical timing.

 

We have a 5 gas test here in Calif. Post ALL the numbers.