Hey guys, my father in law is having problems with his vehicle and I trust your guy's judgements. I know jeeps and dodges are similar so maybe you can give me a general idea. When he was driving the spedometer would drop and kick back up and the truck would hesitate when this happened. I figured the needle dropping and coming back up is the speed sensor. But then he would give it gas and it was at like 4000 rpm's and the truck was only going like 35 or 40. Its a 96-99 i believe and its a jeep grand cherokee 4x4 auto v8. Thanks for any help.

 

TPS maybe? RPM surges or slipping? Might need a new Gov solenoid and Gov switch(transducer).

 

Good old ZJ! I had two of them, a '95 & a '98 (well technically they were the ex's daily drivers).
I'd start with the TPS, myself. Would cause all the symptoms you describe...

 

my understanding was that the rpm surged when the spedometer quit working but only for a second then it kicked back on thats why i was suspicious of that being the speed sensor, otherwise i believe that he was trying to huury up and drive it home and the rpms were high and it didnt seem like he was going very fast so almost like the tranny was slipping. would the tps prevent the tranny from working with the motor consistantly?

 

any way to test the tps or just have to get a new one???

 

You can test it with a multi meter and a Haynes manual for the test procedure. Look in the FAQ section anb download the 2001 FSM manual. It's close enough for what you want.

 

wouldnt that just make it not shift properly? or would it cause it to not speed up with the rate of the motor/ thanks

 

Speed sensor would have more affect on the speedo, and may cause the trans to do odd and strange things....

 

It's kind of hard to diagnose a problem when the person asking isn't the same person who was driving it at the time.

 

the rpms were high because he was giving it gas but he just wasnt moving very fast, it didnt just spike up without throttle. sorry should have specified, so does it still sound like tps or speed sensor?