So I've been having this problem for a while with cold starts... My vehicle is in a garage usually, however about 3 weeks ago I left it in a parking lot. (cold temperatures... Michigan) The next morning when I started it, the car idled immediately at ~500 RPM, no throttle response, and seeming like it was camming like a muscle car. No MIL light came on throughout. This kept on for around 10 seconds then the car was fine. Recently it has been happening even when the car is in the garage and just this morning it wouldn't stop until I turned the car off. It then began surging and intermittently doing the same camming sound with no throttle response, whether accelerating or coasting. Still no MIL light. This continued until it reached OT.
I hooked it up to my computer tonight with the ECT reading ~140 and immediately it began doing the same thing at idle ~540 RPM. I noted that the short term fuel trim on bank 1 was reading -20.3% (lean) and bank 2 was reading 30.7% (rich). TPS was a bit off reading 13.8% at idle and 93% at WOT. The IAT, ECT, MAF, and MAP all read fine... I'm guessing the head gasket on bank 1 had a pinhole leak that would seal up at OT but progressively got worse. A colleague suggested before the test that the oil on my K&N filter (I cleaned and re-oiled it 2 months-ish ago) could have leaked through and residue could have hit the MAF sensor. Any thoughts?
I hooked it up to my computer tonight with the ECT reading ~140 and immediately it began doing the same thing at idle ~540 RPM. I noted that the short term fuel trim on bank 1 was reading -20.3% (lean) and bank 2 was reading 30.7% (rich). TPS was a bit off reading 13.8% at idle and 93% at WOT. The IAT, ECT, MAF, and MAP all read fine... I'm guessing the head gasket on bank 1 had a pinhole leak that would seal up at OT but progressively got worse. A colleague suggested before the test that the oil on my K&N filter (I cleaned and re-oiled it 2 months-ish ago) could have leaked through and residue could have hit the MAF sensor. Any thoughts?