Engine surges need help

[Frank S. fr Ohio]

I have 20,000 plus mile on a 1999 auto with 354 rear. Just recently experience a a problem with the engine. After driving for about 20 minutes on interstate the engine will monentarily rev up with the rpm likewise going up, something like tapping your foot on the accelerator very briefly. It does this without any load in the truck or towing anything. This happens on level roadway without any wind rsistence and I have experienced it without cruise controll on and not accelerating. I've noticed it happening around 50mph and above. Any help or advice would be greatly appreciated.



This is my first post but have followed this site since it started. Truck is stock.



Frank S Ohio

 

[Todd T]

it could be your MAP sensor or more than likely, your Camshaft position sensor. a loss of signal on the map can do that, or die monetarily depending on which side it looses. and the Cam sensor can do the same. since you dont have a box in the harness of the MAP sensor i would start with the Cam sensor. you can put a scan tool on it and try to monitor those sensors along with the speed sensor and try to catch it. or your dealer can put what they call a "co-pilot" on it to do the same.



just an after thought, clean and re-apply some dielectric grease, to your speed sensor first. its on the tailshaft of the transmission, it has three wires coming out of it, you cant miss it.

 

[Frank S. fr Ohio]

Engine surges

Todd T Thanks for the response. I didn't get back sooner because my computer temporarily died and i just got it back up and unning.

I'm still having the same problem only now it is happening more frequently and at more and different speeds.

I guess I will have to take it to the "Dealer" but dont think I have any choice.



I will try the dielectric grease on the speed sensor first.



Anyone else have any suggesions about my problem? Any TSB's?



Thanks again Todd Frank S Ohio