[irbf]

Problem still not fixed. Have been driving the car and putting up with this. After replacement of the O2 sensor the car seemed fine for about 15 trips. The symptom then came back and has gotten gradually worse.

Once in awhile it will throw the 1133 O2 code.

I did find that the thermostat was sticking open and replaced it. This made a significant difference in fuel economy but did not solve stumble problem.

Once the engine finishes going through its fits (seems to start after ECU goes into closed loop) about 60 seconds into running it stops stumbling then runs fine.

So start, at closed loop stumble perhaps stall, then about 60 seconds clears up.

I have also noticed a steady clicking noise while in the car from the engine compartment that seems to be at a steady 5hz frequency at idle. Sounds almost like a bad plug wire and arching but have not found this at all.

I have two of these cars and so swapped a known good MAF sensor and this did not solve the issue.

This chump is stumped...