hello all I am very new to the jeep scene. I just bought my first one. I have a 1987 cherokee w/4.0 I6 and an automatic tranny. it kinda jolts when I am moving but not heavy on the throttle. its almost as if I had shut the motor off and back on again in a split second or maybe a hick-up. but the only thing I notice is that the tach drops a little and then it back to normal until it happens again. it seems to idle smooth but high about 950RPM but if I ease into the throttle it might do it but not always. if I get on it and then hold it about 1500 to 2500 rpm it will do it as well.

the gentleman that I bought it from said that his shop replaced an injector and it was ok for a little while and then it came back again (it didn't do it when I test drove it.)

I think it might be the tranny but I thought that some one who has delt with this before may be able to help me.

 

if it helps, I changed the air fiter because it was half soaked with oil, cap, rotor, plugs and wires gapped to 0.35 but that didn't seem to help.

 

well the only thing that comes to mind is the TPS may be out of wack, is the jeep throwing any codes?

-Kyle

 

not that I can see or pull up but I don't have the proper scan tool.

Is the tps adjustable on these models?

 

yes they are.

let me find a couple of good links for you

-Kyle

 

checking and adjusting the TPS
http://autorepair.about.com/library/faqs/bl232i.htm

use this to check for codes.
http://go.jeep-xj.info/HowtoECUcodes.htm

-Kyle

 

thank you Kyle I will try that tomorrow and get back to you I hope that is all it is!!

 

well that wasn't it. thank you for the help. I guess I am going to have to take it to a shop to look it over.

thank you again!!
Brandon

 

Where all the injectors replaced?

 

no just one.
I check them all hoping to find a bad one but they all where about 16.9-17.2 ohms. My manual says they should be between 3-6 ohms, but I don't belive that they all could be bad and still run (let alone good). so I just assumed that because the lowest setting on my meter was 200 ohms that I needed to get a different one or have someone else check them for me.

 

ok guys got the problem fixed! all that was caused by the crank sensor! but I drove it around for about 30 min. and it didn't jerk again so I think I will be good.