For the last few weeks I've had a problem (problems?) that I can't quite seem to nail down. The main symptom is an annoying stumble at part throttle. It feels a bit like a plug wire starting to fry on a header (I've had that happen before), so I replaced the wires. No help. So I tried new plugs, cap, rotor (can't hurt anyway). No help. I cleaned the IAB and the EGR, and replaced the TPS because it seemed to give inconsistent voltage as I moved it through its range. Nope. Then I did what I probably should have done 1st, a quick check. It gave me a 44 and 94, so I replaced the TAD solenoid that had 12v at both terminals. The codes went away and that seemed to fix it - for about 2 days, then the problem came back. I replaced the TFI module out of desperation, and that seemed to fix it. For another 2 days. I then installed a fuel pressure gauge, did another quick check and a cylinder balance check.
Here's what I've got now: a code 41 (lean right HEGO), cylinder #6 reads low on the second CB cycle (OK on the 1st), and after I turn off the motor the fuel pressure goes down to 0 in about 10 min. It should hold for a lot longer, no? I'm guessing this points to a leaking fuel injector on the #6 cylinder. Perhaps the EEC is trying to lean the overall mixture to compensate for leaky injector on the left, making the O2 sensor on the right read lean?
Here's what I've got now: a code 41 (lean right HEGO), cylinder #6 reads low on the second CB cycle (OK on the 1st), and after I turn off the motor the fuel pressure goes down to 0 in about 10 min. It should hold for a lot longer, no? I'm guessing this points to a leaking fuel injector on the #6 cylinder. Perhaps the EEC is trying to lean the overall mixture to compensate for leaky injector on the left, making the O2 sensor on the right read lean?
