Recap...
I recently had dummy cats installed and the car ran fine. I parked it at work for about an hour and a half. It started up fine but when I got to a light, the idle was crap and it seemed to be misfiring.

I just scanned it and these are some of the significant results.

*all closed loop, no trouble codes.
- O2 sensor at idle, .800 mv range. (I know that is rich but it doesn't set a code).
- O2 seems to work fine above idle. Meaning that it fluxuates between lean and rich.
- Block learn is 108.
- Integrator in 80.

Two problems that I know of are that my passenger side header collector gasket is leaking pretty bad and, while investigating a low "thubthubthub" sound, I noticed that the bracket holding the ignition coil was loose. A quick check revealed the intake manifold bolt to be loose. Even though I tightened it, the engine still seems to be misfiring.

Besides the obvious, should I be looking into anything else?

Any push in the right direction would be greatly appreciated.

Scott

P.S. And just for poops and giggles, I got a flat from a nail in my new tire.

 

With the fuel trim maxed out I would look for a stuck open injector or some other way for unmeterd fuel to be sucked in. Also make sure the ignition system is ok.

 

Am I correct in assuming that you mean plugs, wires, cap and rotor and nothing else?


Two more questions:

1. How do you check for a stuck injector?

2. Could the fuel vapor canister cause a problem like this?

Thanks again.

 

I would pull all of the plugs and for any that have more soot on them than others. The evap canister could cause a problem like this if it was full of fuel and the purge solenoid was stuck on.