I own a 1994 Dodge Dakota 3.9 V6 automatic and have developed a problem. The truck starts up fine and idles okay, but when I give it gas it bogs down and hesitates. If it shifts into passing gear it gets worse. The only way I can describe it is when you accelerate hard, it sounds like a vehicle would sound if you were to remove the air filter assembly, kind of a deep throaty sound. The problem is I am having trouble getting it up to 65MPH on the highway and have never had a problem with it before. So far I have replaced the plug wires, I found the starter coil wire had gone bad, and replaced the plugs last night with no difference. Anyone have any other ideas? Also sounds like a large rattling sound coming from the engine, usually stops this sound at 45 mph.

 

My guess is your intake plenum is bad. This is a common problem with these types of engines. You need to take off the intake and replace the lower gasket. If you need we have a service manual in the FAQ in this section.

 

Maybe clogged cat?

 

Clogged cat, sounds like it may be...when you say bad intake plenum, does that just mean the gasket is bad or do I need a new intake as well?

 

Just the gasket.

 

you have the on set of a clogged cat my guess..

 

I'm going to throw one more idea out there... maybe a bad TPS? I'd say in order of likelyness probably clogged cat, bad TPS and then bad plenum.

 

my truck did that and it was the fuel pump the problem started out inter meadit and grew worse till i coudent use more than 1/4 throtel

 

Sounding like it could be a number of things...I replaced the TPS about 5000 miles ago, so I don't think it would be that. I'm leaning more toward a clogged catalytic converter, would that make rattle sounds like a heat shield rattle? I know the shield isn't rattling because I removed the one that was rattling. Is there any way I can test it to see if it is they catalytic? Thanks for all the responses, I really want to fix this quick.

 

The cat can rattle if the honeycomb starts to break apart. Thats what happened to mine before I cut it out! But a cat can be clogged without being broken apart. Typically, clogged cats will get HOTTT. Drive the truck around really pushing the engine hard for a while and then try taking the temperature of the cat. If you have an optical thermometer, or putting your hand near it, or looking at it and seeing if its glowing red. Those are the only ways I know to test it!