Wacky Stuff

96 4.0, it has been momentarily stuttering or trying to stall, usually when it is cold or for the first couple of hundred meters after a hot start for the last few months since winter hit.

Yesterday it ran really bad for about half an hour, it was running really rich. I checked the CEL codes with the key method and think I read a 14 code, but couldn't get it to repeat. The odd thing is, if it was a 14 code it should have lite up the CEL with the engine running? Maybe I misread the codes and mistook 55 code as a 14 (it was 3 A.M. and I wasn't exactly wide awake).

Darned if I know, as bad and as rich as it was running yesterday it seems it should have had some sort of CEL or code.

Runs fine now and has been since yesterday, an occasional miss and an occasional stutter for the first few minutes after a start. But nothing like it was doing yesterday. I kind of wish it would crap out completely so I could find the problem.

Any ideas?

Cracked exhaust manifold is a possible. Would explain running rich, small crack would prob seal itself up pretty quick in warm weather. Takes a little longer to warm up enough to expand in the cold. My crack is more noticeable with the current weather.

My XJ too is doing a bit of weird stuff at cold start in addition to the usual hot start symptoms. The hot start symptoms only when it is restarted about 10 minutes +/- after it is shut down and it do not all the time. No biggie on that one. The one that concerns me though is the cold start when the temperature is in the 30 to 40 degree range here in North East FL. I am not sure if it does run rich because I have not taken the time to check but it do stumble for a little when load is applied. I attribute it to the IAC.

The OEM exhaust manifold is cracked where the pipe from cylinders 4,5 and 6 enters the collector. Would that affect the first few minutes after a cold start? I do not know.

Since it's a 96, you might also have an OBD II plug
under the dash. A scanner might give you a pending
code, even without a CEL, that would narrow it down...?

Wild guess, sticky EGR valve, rare for sure. Not sure your year even has one though. I get something like that after a hot shut down and the restart is rough for like 30 seconds, warm weather only and maybe once in 50 starts. I let it clear before driving and then its good. Random crap :banghead: