running rough when warm

[gwaker]

My 1991 sport has recently started to run rough once warm. When I start it in the morning or any time it has sat for more than 4 to 5 hours it runs great, but if I shut it off for a few minutes and then restart it it runs like it is running on 5 cyl. I can drive it but it never cleans up kinda like a dead cyl. I pulled the spark plug wires off one at a time to see what cyl was missing and the one that didn't make any difference was of course the hardest one to get to ( the back one on the pass side) It was getting spark to the wire but I put new plugs in today and it didn't make any difference still missing. Like I said before if I let it set for 4 to 5 hours it will start up and run fine no misses at all . anybody have any ideas on this one. would a fuel injector do this it has me puzzled .thanks in advance for any help on this one .

 

[KobeJ05]

My 1991 sport has recently started to run rough once warm. When I start it in the morning or any time it has sat for more than 4 to 5 hours it runs great, but if I shut it off for a few minutes and then restart it it runs like it is running on 5 cyl. I can drive it but it never cleans up kinda like a dead cyl. I pulled the spark plug wires off one at a time to see what cyl was missing and the one that didn't make any difference was of course the hardest one to get to ( the back one on the pass side) It was getting spark to the wire but I put new plugs in today and it didn't make any difference still missing. Like I said before if I let it set for 4 to 5 hours it will start up and run fine no misses at all . anybody have any ideas on this one. would a fuel injector do this it has me puzzled .thanks in advance for any help on this one .

change the plugs and wires fuel filter and run the cleaner in the tank

 

[marragtop]

You can also try switching the 'bad' wire with another wire to see if the miss moves to the other cylinder. If so, then you know the wire is the problem. If the miss stays with the original cylinder, then it could be a plug or coil problem.

 

[gwaker]

I'll try switching the wires. But they are pretty new maybe a year old. Put the fuel injector cleaner in a few days back didn't seem to help. Someone told me that it could be an injector going bad on me.I 'm guessing that it would be on #6 cyl. (all the way in the back on the pass side) not the easist one to get to. I thought about trying to pull connector off at injector to see what difference it makes. Seems to me though that if it was a wire or fuel filter it would do it all the time not just when it's warm. Thanks for the ideas I'm off to go check it out.

 

[marragtop]

It could be the injector, but switching the wires will help eliminate a wire problem.

 

[gwaker]

I switched wires and problem still there. When it's running good I can hear all the injectors clicking and when it's running bad I can hear all the injectors clicking ( stethoscope) I'm guessing that somehow the fuel stops flowing through the injector on that cylinder.Is that possible.

 

[gwaker]

OK now i pulled the coil off and checked the injector for continuity and there was none on the one I think is bad I checked another one and there was continuity in that one, So i'm leaning towards a bad injector. does anybody have any recommendations of a particular brand or just what the stores sell .around here they are appx 70 smackers. sound about right?

 

[gwaker]

It was the injector. Put one in and so far running real good. Thanks for the suggestions everybody.