I have an 01 Dodge Dakota 3.9 2X4 with 104,000 miles. When I am driving slow or in town it runs fine. When i am on the highway going a little faster it suddenly looses power when i have the pedal held steady in one spot. It will gradually slow down unless i put it to the floor, then it will take off and run great for a few minutes, and then start doing it again after a while. It happens everyday. Any ideas? Thanks.

 

Welcome to the forum..

Do you have any codes stored from the PCM? You can turn the ignition on and off 3 times, on the 3rd time leave it in the on position and any trouble codes will display in the odometer. First thing to suspect is the Throttle Position Sensor. Check the center wire on the wire connector at the TPS for voltage. With the throttle closed, engine off and ignition on, there should be between .35 to .90 volts on the center wire. Then slowly open the throttle by hand. The voltage should slowly increase and be about 4.5 volts with the throttle wide open. You may have to take your meter with you and go for a test drive, get the truck to act up then test the TPS on the side of the road to check it for sure. Usually when the TPS is bad it will cause hard starting unless the pedal is held to the floor, but from what you describe it sounds like there is a dead spot in the TPS somewhere.

Jimmy

 

yeah like silver said check your sensors on your intake (throttle, idle air, MAP) and see what that does.....if those check out, could be your crankshaft position sensor....

 

I checked the voltage on the TPS and it goes from .58 closed, up to 3.80 when it is wide open. And there are no codes on the PCM. One of the O2 sensors set it off a few months ago and I just drove with it that way and the light turned off here a few weeks ago. Thanks.

 

mAYBE A map SENSOR.

Take it to AutoZone they can hook up a computer to it for free and tell you a little more whats going on.

Good luck

 

Could it be the crank or cam sensor? Should it run different with the cam sensor unpluged? I unplugged it and it ran the same, no change.

 

It has been running great lately. Then tonight after driving it about 15 miles, it was idling rough when i got home. I opened the hood and the cat converter on the passenger side was cherry red. Is it plugged. Still no CEL. No codes. And exhaust sounded different than it normally does, and smells the same. Does not smell like "rotten eggs"..

Thanks.

 

"the cat converter on the passenger side was cherry red"

Sounds like a bad cat to me. Does it make a "rattling" or grinding sound when it's idling rough? You can get back pressure on an engine bank that robs you of power. I thought that was my problem, random misfire code on bank 1. Replaced the cats and O2 sensors, however mine is mechanical in nature, bad cam or timing chain.

 

No it does not make a rattling sound or anything like that. The sound of the exhaust out the pipe does sound plugged up when the converter gets red.

 

I'd say replace them before you hurt the motor.