I have a 2001 Dodge Dakota SLT. 4.7 V8, CAT back duel exhaust, K&N air filter. That's about it for the truck.

When driving on the freeway lately, If I keep a constant speed limit (say 65mph) I can hear my engine RPM's fluctuating from about 500 rpm's to 1000 rpm's.

It's also starting to do this at lower speeds as well when driving around town.

So bottom line is this. If I maintain a constant speed, my rpm's are going up and down from 500 rpm's to 1000 rpm's.

What would be the cause of this?

Thanks for the help.

 

Could be tps going bad

 

90% chance the TPS is bad. I had it happen on my old Ram. Replaced it, and it instantly fixed the problem. Do it now because your tranny overheats with the fluctuating RPM's.

 

i agree tps, it fixed my same issue, good point about the trans. the tps is cheap and easy to replace.

 

Thanks for the replys folks. Much appreciated. I'll be replacing it this weekend.

 

100% that the TPS is the problem. I also have a 2001, 4.7 liter and my TPS went about a year ago. Haven't had an issue since I replaced it.

 

not to sound like and idiot but what is a tps

 

Throttle Position Sensor. Tells the computer how much fuel to dump in the engine.

 

Also can be used to tell the tranny when to kick down into a lower gear

 

this is good to know my truck just started with this also. Could this also help with the idle going up and down when in park?