While my truck is idoling, it keeps reving, and RPM jumps up and down? Also I noticed at about 60 mph, the truck seems to do the same thing, fluctuates, on the RPM's...anyone have this problem? or any suggestions? THANK YOU!

 

My initial thought was vacuum leak......check your hoses, intake mainfold gasket etc. On the old stuff (pre-computers) we would run the motor and then spray either wd-40 or water on any suspect areas and if the idle returned to normal after spraying, you had temporarily resolved the leak with a liquid seal. With all of the onboard diagnostics available today, I have seen back-yard mechanic friends replace really expensive parts only to find out the part wasn't the problem but a friggin sensor or sensor connector harness. As much as it hurts to admit it, I've resolved myself to letting the diagnostic software isolate any problems before I spend ANY money on hard parts.

Good luck and let us know how it goes.

Jer

 

I'd suspect the TPS on the LA motors or the electronic throttle body on the Hemi. I'd also look at the IAC valve and possibly the MAP sensor. Vacuum leaks can also do this as mentioned. Be sure to isolate and look for voltage jumps on a scanner that can tap into the above sensors.

 

I have a 2002 ram 1500quadcab with the 4.7 and my truck was idleing reallybadwhen i would start it theengine would idle around 1500 for 10 to 15 sec. Then when i was drivingthe trannsmisson would shift alot in and out of overdrive. What it came down to was a dirty throttle body. I took the Throttle body off and cleaned with throttle body cleaner andthe idle went to normal.The only thing i have to do is to replace the throttle postion sensor orwhat is known as aTPS sensor and it will run great.

Hope this helps.