Hello everyone,
This is my first post here and did some searching around but didn't see anything, although I could be using the wrong wording. Anyway I have noticed lately that my truck, 1997 Dakota SLT 4x4 3.9L Manual, is losing power. It seems to be getting progressively worse, when I first noticed this last week it was around 3.5k RPM. Now it is happening around 3k RPM. It seems to hit a wall and will not accelerate past 3 - 3.5k in any gear. Even when just revving it in neutral it seems to hit the same wall 2-3 times out of 5. Also I have noticed that when it hits it's "wall" the engine rattles or knocks (kinda hard to describe). I am scheduled to be doing a "tune up" with a buddy next weekend but by that time I am worried it will be un-driveable by that time. I am hoping that it is something simple like a vacuum leak or worn out plugs and wires. I am more of a computer nerd but have some mechanical skills.
Hopefully someone out there has some ideas to check.
Daniel
This is my first post here and did some searching around but didn't see anything, although I could be using the wrong wording. Anyway I have noticed lately that my truck, 1997 Dakota SLT 4x4 3.9L Manual, is losing power. It seems to be getting progressively worse, when I first noticed this last week it was around 3.5k RPM. Now it is happening around 3k RPM. It seems to hit a wall and will not accelerate past 3 - 3.5k in any gear. Even when just revving it in neutral it seems to hit the same wall 2-3 times out of 5. Also I have noticed that when it hits it's "wall" the engine rattles or knocks (kinda hard to describe). I am scheduled to be doing a "tune up" with a buddy next weekend but by that time I am worried it will be un-driveable by that time. I am hoping that it is something simple like a vacuum leak or worn out plugs and wires. I am more of a computer nerd but have some mechanical skills.
Hopefully someone out there has some ideas to check.
Daniel
All Star
Welcome to DF first of all.
Id check all the stupid things first. Oil, plugs, wires, dist cap, air filter and in the mean time Id get a can of seafoam and run it thru your gas tank. I have run it thru on a half a tank for a more concentrated effect and I think you might want to do that as well. Maybe just checking all those things your notice something else that will help to figure it out
Id check all the stupid things first. Oil, plugs, wires, dist cap, air filter and in the mean time Id get a can of seafoam and run it thru your gas tank. I have run it thru on a half a tank for a more concentrated effect and I think you might want to do that as well. Maybe just checking all those things your notice something else that will help to figure it out
Thanks for the quick response, I'll definitely keep an eye open to see if it is any of the stupid things. We already plan on doing the plugs, wires, and cap. Checking the filters and all that. I picked up a can of seafoam tonight and put that in the tank to see what if it helps any, I'm sure it won't hurt, it's been a long time since any cleaners like that have been run. One thing that I realized I forgot to mention in the first post is that there is about 135k miles on it. I have not had any real problems with this truck they seem really dependable.
All Star
Mine has 132K mi and 95% of the issues are relatided to my own stupidity lol
Sea foam is great stuff! I run it thru my gas often and Ive run it thru my oil too, next is to clean my intake with it
The only other thing I can think of would be to take your trhottle body of and clean it. maybe its all mucked up. Or if you want a little performance you can put the 5.2/5.9 TB on it.
Sea foam is great stuff! I run it thru my gas often and Ive run it thru my oil too, next is to clean my intake with it
The only other thing I can think of would be to take your trhottle body of and clean it. maybe its all mucked up. Or if you want a little performance you can put the 5.2/5.9 TB on it.
Well this past weekend me and a buddy did replaced the fuel pump assembly. It was surprisingly easy doing the bed tilt method. However that was not the problem. 
So, after a little more of hunting around we decided to pull the O2 sensor to see if it is a clogged Cat or muffler. That made the truck stupid loud but answered the question. I instantly had more power and the truck could move again. So, the cat is getting replaced tomorrow. If only we had checked that first. Live and learn!
So, after a little more of hunting around we decided to pull the O2 sensor to see if it is a clogged Cat or muffler. That made the truck stupid loud but answered the question. I instantly had more power and the truck could move again. So, the cat is getting replaced tomorrow. If only we had checked that first. Live and learn!
Record Breaker
The plenum is most likely leaking!!! That is also what kills the cat. Cats very rarely fail without something else causing it.