95 Laredo Missfire driving me crazy!!!!
 

Hello I have a 95 Laredo that has a really rough idle and a miss in it until the engine gets to 2250 rpm. Before I go any further I will give yall a little history about what I was told when I bought the jeep. I was told it had a new distributer, new wires and plugs. a new iac and a new coil. When I bought the jeep I thought the problem was a vacuum leak and would be a easy fix.... boy was I wrong.

I have gotten the codes for the jeep and got code 27, 24, 41. I hooked up a vacuum gauge to the intake manifold and the reading fluctuated between 18 and 10. I looked up in the manual and that said it could be a due to a vacuum leak at the intake manifold or something going on with the fuel injectors. Code 27 also talks about a vacuum leak or something with the fuel injectors. Code 24 said something about the tps sensor not communicating with the map sensor and 41 said something about the alternator.

My confusion now is coming from the results I am getting from the test of the vacuum leak and not being able find it and the fuel injectors all having the correct resistance and listening to them with a screwdriver they were all firing.

I also have checked the ckp and the cmp with a scope and back probed them. checked the timing and changed the tps.

Could it be the ecm, the wiring harness for the fuel injectors? ahahahaha

What would yall do? I am all ears.

I also forgot to add that I have done a compression test and all cylinders passed. This jeep is driving me crazy.

I had similar issues on my 96 ZJ. Rough Idle, sputtering at low RPMs. Surging while stopped in gear, would sometimes die at idle. Crank Position Sensor solved all of the above.

AND don't waste your money on anything other than Genuine Mopar sensors. Cost a little more, but you KNOW they'll work.

Using after market sensors on your Jeep is like buying a cubic zirconia ring for your wife and then telling her "It looks like a real diamond". Trust me friend, you'll regret it!