Last week or so, the 2.8 has been running like crap..first it was just that the tach needle would twitch at idle..then it got worse, so now it fluctuates all the time, even when running..it nearly died on the highway on Saturday it was stuttering so bad. Vacuum tests out good, IAC is brand new (as of today), MAF sensor checks out fine, no loose wires, no codes...that was all I could think to check. It starts up quickly every time, and the only other thing I have touched on it recently was the radiator (the highway incident happened on the way to the wrecker's to get a replacement, which went in the next morning). Anything else I can check? I'm all out of ideas!
Thanks for any help!

 

Have you checked your throttle position sensor? No one else has replied so I'm just trying to toss an idea out or two. Wayyy long shot here but...what about the EGR? Could it be freaking out?

 

Thanks Nixon..I was just going to check the TPS sensor tonight. Is there another way to test it besides unplugging it? I like to double check things.

 

Yours is a non-adjustable type right? Uhm..with a multimeter I know there's a way to check the TPS sensor's output to see if it's correct, but I don't remember how or what the numbers are...maybe someone else here does.. I know it was brought up in an earlier post....

 

try just a basic tune up, wires and cap and rotar. Mine was like that but those things just cleared it right up

 

hmm..well I'll do a bit of searching then. Uplugging the TPS didn't have any effect..ran just as crappy without as it did with. What about a connector rod bearing? Someone I know suggested that, but it was after he'd drank half a bottle of scotch, and when he thought about it again the next day he said he didn't think it was likely. I don't know anything about conn rod bearings so i have no idea what the symptoms should be..

 

How old is your fuel filter? If it was like mine "completly oroginal from 85" and weighted about 2 pounds then try replacing that. Maybe the fuel injectors are sticking? Or fuel pump? Since its sputtering these would be my guess.

 

lol Wish it were as simple as the fuel filter..but that got changed in the summer. If the fuel pump was dying, wouldn't it have a hard time starting too? I'm thinking maybe if there is a valve or something between the fuel pump and the injectors, that could be choking it out??
But I don't know what, if anything is between the two..have never gotten it apart that far.

 

I'd put money on an open plug wire or at least a secondary ignition problem.

 

My car used to do that, it was a short in the wiring between the ign mod. and the injectors. the mod. wasn't telling them to fire.

 

Simple check:

If you haven't checked the cap and rotor, do it...just loosen the 2 holddown screws out..they should loosen up but not come out because they've got a washer stuck on them or something...slide the cap off and look at the terminals, and on the conductor piece on the rotor..look for corrosion..if there is some, use a wire brush or fine sandpaper to carefully take some of it off, and see how it works then..but if you take too much off the terminals it'll screw things up so be really careful if you try this..it's better to just replace the cap and rotor. They're not much money. A higher quality one is like $20...Blue Streak it's called. I don't like the Accel ones or others because they're either nasily colored, like brown and tan, or bright red...I have no red anywhere on my car.