Ok. It's an ej22. Plugs, wires, coil and ignitor are tested and all seem to work fine. Injectors don't seem to be the issue either, nor fpr. I've gotten misfire codes for all cylinders, but lately only 2 and 3 are coding (I'm assuming they are just the lucky winners lately). Driving, it runs fine when cold, then seems to gradually get worse. It seems to react to both throttle and rpms. It starts to develop issues somewhere in the 3k-4k range, but outside that runs ok, then as it gets warmer it pretty much misfires from 3.5k up. It also gets more throttle-dependant as it warms up - it becomes a challenge finding that one happy spot where it doesn't misfire, lol. It uses a buttload of gas too. Like... 14mpg. The only codes it has ever given me are misfires. I was thinking it could be the coolant temp sensor causing it to stay in open loop, but I would think it would either code on me for the sensor, or code on me for it sticking around in open loop. :\ And I'd think that an o2 sensor failure would give me a more abrupt change in behavior between cold and warm (whether it is bad enough to code or not). Any ideas?
define. This sounds a lot like bad plugs. just because they're making spark doesn't mean it's good spark. my Ex's '96 OB (Auto trans, so 2.5....but similar) was throwing misfire codes on 3 cylinders, those 3 had champions, and the 4th had an NGK which was in much worse condition but still was sparking stronger than the others. spent $10 on a set of NGKs, and it ran perfectly. next I'd clean our your MAF and IAC.
Alright, I might clean the maf and iac tonight or tomorrow. I'm having trouble figuring out how that'd do it though, since it runs perfectly normal when it's cold. .-. I'll update upon results.
Hi again. I finally got over my stubbornness and swapped out the maf (junkyard parts, just felt like it I guess), and put in new plugs (NGK V-Power). Nothing. :\ I'm considering ecu/grounding issues maybe now...
Not to be the bearer of possible bad news, but it might be an issue with sunken valve guides. You said that you did a compression test, and a leakdown test. What temperature was the motor at when you performed these tests? I have seen some 2.5 DOHC's that have minor bent valves that are fine when cold, but when they warm up, they start to mis-fire. I would doubt that you actually have bent valves on a 2.2L, but I have seen quite a few that have dropped the valve guides which holds the valve open, creating a mis.
Yeah, I think that's pretty unlikely, because the heads were redone a little under 25k ago. Plus, it doesn't sound like it'd behave as consistently inconsistent as it does. I don't remember if the engine was warm or cold when we did the tests though :\
