04 Envoy with 199K on it started flashing the CEL. My wife had said it seemed to lack some power when starting off a month or two ago. I added some techron then to clean it out some. Didn't seem to help much, but the car still accelerated OK. It is not like a night and day difference in acceleration. But yesterday the CEL started to flash when starting off while going up hill. No codes though. The plugs and fuel filter were changed at 147K. Could the AC Delco Iridiums be dead after 50K? The originals actually made it to 147K before it start having issues.
One other thing is the when the AC is on you can hear a wining sound that comes and goes, but mostly at lower to mid rpms when starting off. This is not a normal sound and I think it started over the summer sometime. It made this sound all three times I saw the CEL flash yesterday. I saw some other posts about vibrations like bad motor mounts causing a flashing CEL. It isn't vibrating like bad motor mounts I have had to have those replaced before. Could the bearings in the AC compressor being going out and vibrating something to cause a fake misfire flashing CEL?
So much easier when something just breaks or gives an error code.
One other thing is the when the AC is on you can hear a wining sound that comes and goes, but mostly at lower to mid rpms when starting off. This is not a normal sound and I think it started over the summer sometime. It made this sound all three times I saw the CEL flash yesterday. I saw some other posts about vibrations like bad motor mounts causing a flashing CEL. It isn't vibrating like bad motor mounts I have had to have those replaced before. Could the bearings in the AC compressor being going out and vibrating something to cause a fake misfire flashing CEL?
So much easier when something just breaks or gives an error code.