Hello Everyone,

I have a most confusing problem with my truck and I am asking for all the help I can get before I start rage-replacing parts. I have just arrived back to my house in the city from the family farm and I'm here to lay out a big big trouble I am having with my pickup.

First off I will start with the description. I have a 1997 dodge dakota slt 4x4 with a v6 3.9L engine, standard 5 speed transmission, and 2" lift kit with 33" tires, and it has about 250K on it. Hopefully that should be good for now.

Secondly the troubles I am having are:

I cant get the truck to go faster than 50mph.
Gas consumption is huge. (1/2 tank to 70 miles)
I can't maintain any real speed. even a little hill slows it down
It powers out anywhere between 2500-2700rpm in third or fourth
There is no accelleration whatsoever.

Now I can describe some things I have done and looked at. The check engine lights been on so I took it in to the local dodge dealership and the codes read out that cylinder 6 was misfiring. o2 sensor was good and reading the correct voltages from what I reasearched. .84V I do believe. everything else checked out alright as well. Anyhow, common sense pointed me toward checking the plugs and wires. I pulled a plug and found that they were completly worn out, I thought that was great and I changed all plugs and wires along with the cap and rotor, didnt cost more than 100 bucks and some maitenence was done that needed to be done anyway. Excited, I took the truck for a spin on the hiway to welcome the new power finding out there was none to be welcomed. I have always experienced a noticable difference in any truck i've tuned up but this time no. plus, the check engine light came back on when i got back into the city. It always goes out when I am on the hiway. Well, what the heck. Im completly baffeled. Idiling, the truck doesnt seem to miss. In the lot,it responds and revs up just fine. There are a couple other pieces that may or may not be helpful.

In the summer i found the lower vaccum port on the right side of the intake didnt have anything on it. I searched high and low for a hose that may have come off but found nothing. I couldnt find any info on the internet and searched the scrapyard for engines like mine and found it just had a rubber boot on it so I put one on. dont know if thats useful but maybe.

The other thing ive noticed when i am climbing through the valley which isnt too steep, maybe 4% grade at best i dont have the power to get up it even in third gear, when i shift down to second she starts to climb and accelerate up untin about 2700 rpm and then the truck powers out and barely makes it up the hill. I do believe this is useful, but once again my brain is in exhausted trying to figure out what it is.

Now without putting this truck on a dyno and giving some hard numbers I think thats about as explanitory as I can be. The truck doesnt make any odd noise, or sputters or backfires. It starts everyday, idles alright even though the cold-start high idle doesnt seem to work either. doesnt use oil, antifreeze is brand new this weekend along with the thermostat. It drives in the city ok. I have checked as much exterior of the surrouding engine bay, nothing seems to be out of order. there is oil in the tranny and rear end. the fuel filter should be alright as the fuel i put in is already filtered. I change oil regularly and really do take care of my truck. I have talked to everyone i can think of and gotten no useful information.

I have been plauged with this trouble for a while now, about 6 months or so and have no success in finding out the trouble. I am at the mercy of the hills in the road and even the wind. I dont believe thats normal for the truck. Hopefully I can get her fixed up before seeding as I will be needing to commute quite a bit. I am thinking some sensor is preventing me from getting the power i need.

I thank you all in advance as I am worn out, frustrated and really exhauseted. It was a long angry drive back home and I gonna get some sleep. Thanks again.

Josh

 

Now that im really paying attention driving around in the city i do also notice when i come uo to an intersection and want to go after stopping, if im in second it doesnt accelerate too well at all.

 

With the engine misfire, it could be that the engine has made the computer go into limp mode, but that is really all that comes to mind with your symptoms.

 

i had maybe the same problem as you, a while back i had to do a clutch replacement which forced me to take the exhaust of the headers, but when i went to put it back on they didn't go on tight enough, it left a small gap, so a couple weeks went by and i decided to finally get to fixing it. well, the fix went fine but when i went to drive it, it could beet a turtle. turns out my CAT was bad, it was blocking the exhaust flow(didn't notice it cause exhaust wasn't on tight at the headers), good at low rpms but anything high forget it lol. So i just cut it off and BAM all my power was back. I would look at your CAT if you haven't already. I hope that helps.

 

I had a 89 mustang gt that when i bought it it would idle and rev just fine but wouldnt do over 55. turned out to be someone switched the plug wires around and the timing was off if it helps any

 

Like drifter58 said, Try your cats. Heard of similar stories

 

Thanks for the replys, i do not have a cat on my truck, it is a pre-cat exhaust on er.

 

is it really possible for the computer to go into a "limp mode". how would somebody go by repairing that. would a bad muffler do the same thing as a bad cat?