1995 Gran Prix 3.1 V6

Engine has a rough idle and a mild shake to it.
In gear at idle, the car will not move itself
Hesitation while accelerating, kinda like you got your foot on the brake...
Exhaust kinda sounds muffled, like it's underwater...
And, the typical tranny bounce from drive to OD is more prominent than normal...

So far the plugs were changed, the fuel filter changed, injector cleaner run through it, and they checked to make sure that the plugs were all firing(they were, and had good color to them).

What do you guys thinkthe problemis???

 

Also, the engine light is not coming on...no codes

 

I had a '91 and all I can say is it sounds like the brakes. It sounds like your emergency brake calipers are stuck, I had sort of the same problem with mine, it affected things at low speeds, but you don't notice it at higher speeds. I'd jack the car up and see if you can rotate the rear wheels easily.

Other than that, you got me.

 

fuel pressure or cat,I'd say...may wanna check the fuel pressure

 

Check all the exhaust to make sure you didn't bend something and close off the exhaust somewhat.

 

Thanks guys... Car belongs to a friend of mine. Brakes are fine, by the way, problem is engine related...

My guess was the cat is clogged. Holding a hand over the exhaust, i didn't feel like it was pushing hard at all. I also tried the "dollar bill over the tailpipe trick" and it didn't suck the bill into the pipe, but it didn't seem like it was letting out the exhaust properly.... I think our next step is to gut the cat and see if it changes anything.

Again, thaks for the replies!

 

Hello! I'm not sure about the correct terminology, but here goes. Mebbe one or more "coil packs" has gone bad. Each coil pack sends spark to two plugs and this is a common failure. Your motor will have a "3-pack" of coils mounted together, each coil connected to two plug wires. Could try looking at coil pack in the dark with engine running, possibly see sparks going to the block instead of plugs. Or check each plug for spark. Or try unplugging plug wires one at a time and see if engine performance varies. I saw this alot on the 2.0's and once on a 1990 3.1 Liter. And be very careful when unplugging these wires if engine running......that spark is like AT&T, it will reach out and touch you. LOL. Let us know.

 

Yeah, I scared the hell outta my buddy when I pulled them off...lol! He had already had them pulled once by a mechanic...both times it caused an expected miss. This tells me that it isn't afiring issuecausing the problem