ok ,back again with my hesitation issue. Vehicle is a 2000 jimmy. I cleaned my MAF,and my cats dont seem pluged. I also used BG intake and fuel system cleaner. This seemed to help a bit with throtle response. My current issue is now narowed down to a hesitation between 1700 and 2100 were the power just falls away untill i cross that gap . MAP sensor is good i do beleive.It also looks like fairly new tune-up parts. On the scanner i showed no misses except a random one in cyl. six. I just replaced my fuel cap today. Again on the scanner at idle my o2s's 1 and 2 bounce between rich and lean and during accel. they show lean. Im trying to find a solution to my problem without dumping tons of money into this thing. Any and all sugestions are aprechiated. Thanks again.

-Mike

 

Does your timing get cut (knock retard) during this RPM range? If so, it could be caused by a noise from the timing set due to a faulty tensioner. The noise can excite the knock sensor causing the PCM to cut timing and decrease performance.

There was a revision in the tensioner to cure a noise from the engine within a certain RPM range. CLICK HERE for the TSB concerning the tensioner.

 

interesting tsb. sure sounds like it could be the issue. if i can today ill get it on a scanner and see what the timing dose could this problem also cause vibration at idle similar to sitting in an escort 4 cyl. at a stop light?

 

well i had an early out at work today so i got some jimmy time. my timing dose not cut out, there is also no real "rattle" coming from the chain area. the only noise there is similar to that is an a/c clutch noise. i did though dig a little deeper into exactly when this happens. almost always its in second gear abould 1/3rd throttle and then accelerating harder past that point seems like the fuel just get shut off, when it cuts out i can floor it and it just sorta dies out then it will finaly kick down and be ok again. what controls the trans. kick down on these cars?

 

The transmission is controlled by the PCM.

 

I guess i should ask what signals the PCM to kick down the trans?

 

A lot of things. TPS, MAP/MAF, Engine RPM... I'm forgetting something...

 

dose anyone control more than another? i figure my map was good because when i unpluged my maf to clean the intake it ran ok with it unpluged, although strangly enough it didnt turn on the MIL. i fugured it would have tripped something. my tps shows properly from zero to a hundered percent on the scanner.