Getting misfires (only noticable at idle, which is wobbly, as though missing, but doesn't always throw a code) in all four cylinders. It has thrown codes a few times, 301, 302, 303, 304. Not all at the same time, but as many as three. No accompanying codes Recently had head gaskets done. Car was running fine before then. Timing belt and all marks are fine. Car has new front o2 sensor, crank sensor, cam sensor, intake air temp sensor, fuel pressure regulator, ignition coil, wires and plugs. Idle air control does actuate and pinching off the line to the throttle body/intake manifold from the purge control valve changes nothing. The car has runs on a map sensor (which I have checked with a hand pump, it starts at 4.35v at no pressure and drops about 1v per 5inHg applied, I don't know if that starting point is a little low?) And responds quickly to any artificial leaks (engine surges and immediately drops back down to it's rough idle). Smoke test showed no leaks. Alternator and battery working fine. Planning on changing the coolant temp sensor this weekend. It has deposits on it. I have not checked compression yet, but this seems an unlikely culprit as the misfires are happening in all cylinders. Throttle position sensor shows 0% with foot off gas and 100% pedal to the metal on the scan tool.
Any ideas? Do map sensor readings make sense? Could coolant sensor be to blame? Anything else I should be looking at?
Tuesday, February 28th, 2012 AT 7:07 PM