Had a thread going about TPS but I kinda got off topic and still need help with power loss. 3.9 4x4. At any speed I can floor the truck. I watch the RPMS climb but the truck slowly gains speed. There is no kick. It kicks in if the cruise is on and needs to accelerate. I have changed the plugs and TPS so far. Any other ideas?

 

transmission slipping?

 

No. It is shifting much better since the TPS has been replaced. The strange thing is if I have the crusie set and it needs to speed up to stay at the correct speed it kicks in just like it should when I push on the gas.

 

My 3.9 was a dog when I bought it. I changed the plugs and wires and it got better. I changed the dist. cap and rotor and it got even better yet. I changed the Map Sensor about 6 weeks ago and now it runs like a champ. I have 178,000+ miles on my truck and it runs great. There are some threads on here about the map sensors. It was about $85 for the map sensor but it made a huge diffence in the way my truck runs.

 

I will look into that ty. I picked up a service manual for the truck so should tell me how to test it I hope.

 

Ok could use some more advice on this. Replacing parts and not getting results. So far I have replaced the TPS, cap and rotor, PCV, and spark plugs. Last night I was going up a pretty steep hill and I wasn't sure I was going to make it up. I know this motor has more I just can't find it. If you guys have more suggestions I would appreciate them. The snow will be flying soon and I am concerned that if I need the power it won't be there.

 

I am beginning to think I should change the spark wires out. From what I am reading the signs of bad wires can cause this symptom when a heavy load is applied. Runs great at slow speeds but when I get on it, it lags. Also I do notice a jerking feeling at higher speeds which would do the same thing.

 

The problem may be the plug wires, especially if they are old or even OEM. The problem could also be the Manifold Absolute Pressure (MAP) sensor. There is a long but very informative post about the MAP sensor and power loss here:

https://dodgeforum.com/forum/2nd-gen...er-solved.html

That post has a lot of good info in it. It may help you fix your truck.

Jimmy

 

I am going to try the wires first since they are cheaper than the MAP sensor. I have the service manual so I believe I will try to figure out the test procedure for the MAP sensor before buying. I also spoke to a friend who is a mechanic and huge Dodge truck fan and he said check the CAT and it could also be the lockout on the transmission. I checked the tailpipe yesterday and I felt what I believe to be enough pressure coming out and it felt pretty warm. Think I will take my infared thermometer and check the temp before and after the CAT also. I have got to get this fixed soon.

 

OK changed the wires. Also went to clean the IAC and well that didn't go so well. I put it back on and it malfunctioned so just went and bought a new one. Truck has even more power now but not all so.... I am down the MAP sensor and Governor pressure sensor and solenoid to look at. I am leaning toward the governor pressure sensor and solenoid simply because the truck feels like it kicking into a higher gear and the hard shift is still present. From what I am reading this may have something to do with the lockout. I am not aware of how this works.

I also took a look at the TV cable and it seems aweful loose but I am not sure how loose it should be. This is one of those fixes I am alittle leary on.