TJ runs rough and has no power

Robert76

New Member
Joined
May 24, 2019
Messages
3
Location
Valparaiso IN
My first time here so thank you for your patience. I have a 97 tj to with a 4.0. It takes some cranking for it to fire up and when it gets warm, it runs really rough and no power. Note the check engine light us NOT on. I've cleaned the throttle body and replaced the IAC
 
Is it throwing a check engine light or any codes? If so, what codes?
 
Have you had the jeep a while or is it new to you?

Does the check engine light come on qhwn the key is in the run position before you start it? We had a guy a few days ago who the po removed the bulb.
 
If there aren’t any codes as you say, then perhaps it is the fuel pump not delivering enough fuel. This would explain the extra long cranking to start and the crappy acceleration. Try turning the key on, but don’t start it. After 10 seconds, then try to start it. If it starts quicker after the pump is primed, then I would suspect weak fuel pump as a candidate.
 
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If your timing is too far off it will act just as you describe. Some bad fuel will do this too. Did this just happen out of the blue? What was going on just before the problems started?
 
Have you checked the compression? Also, have you checked the spark plugs? When is the last time they were done, what plugs were used, and what were they gapped too?
 
A few times I've run in to similar issues like this at my shop. A lot of times the crank sensor will start to fail when it gets hot, even though it won't throw a code. That could take care of your long crank issue too.