When driving normally, and shifting 2500-3000 rpms, my car likes to shake a lot. It doesn't like being driven slowly. Does anyone else have a 2.8 5spd with the same problem or had the same problem. From what I've read, this could be caused by spark plugs and plug gaps. Right now I have champion plugs in. I heard AC Delco plugs were the best. Does anyone know the correct gapping for the 2.8? Any suggestions are greatly appreciated. Thanks.

 

Sounds more like clutch slippage than plugs. But... does it do it all the time? Or only in the rain? I once had some bad shaking on my 86 TA, turns out all it was was a spark plug wire was rubbing on something that wore right through the cable. Whenever it rained, it ran like hell hehe!

 

Actually, now that you mention the clutch, I have realized that my foot will be completely off the clutch and my foot on the gas and it will shake a little bit. but it only does it for a few seconds. It does it near low RPM like when you first start off. An d surprisingly, it didn't do it once in the rain yesterday. It does it more when it's dry out. When I put my new dizzy cap on, the back screw near the firewall must have stripped cause it doesn't tighten and the cap moves a little bit. It started right up with no problem, but maybe that's why. Maybe it moves just enough where the rotor doesnt hit it. If it is the clutch, I want to get a new hydrolic line and a new slave cylinder as well. My brother's S10 slave and line blew and got new ones put in and the clutch pedel is way tighter. Anyone know how much the slave and line go for? Well, if there's any comments on what I said, or anymore suggestions, I'm all ears. Thanks!

 

I'm no expert on what's going on, just tossing some ideas out there from my past experience with a jittery engine.

Well if the distributor cap was anything like on my old 305 they are more like hooks than screws. if you're pushing down trying to screw them in they'll just keep turning and turning and turning. Have a look at the front ones and see if they are just L shaped posts that slide into a notch under the distributors base.

 

Has it ever been smooth? If it's always been like this, has it ever been monkeyed with? Most people don't think about or don't know that some 2.8's are internally balanced and some are externally balanced. If the engines ever been swapped it could have the wrong flywheel. Could also be misbalanced tires, lose lugnuts, lose driveshaft bolts, water/mud/fix a flat in a tire, worn ball joints, etc... So yeah, you'll want to do a visual inspection first, and definitely try observing for potential problems. If it's ignition related I'd expect the tachometer to jump. It could be a clutch or plugs or that distributor... The later 2.8's and 3.1's have a screw down cap, if the holes stripped you might have some play that could cause the rotor to hit the terminals, or have too large a gap. There should be alignment pins on the cap to keep it from moving too far. The threads are in the distributor itself, to fix them you could try tapping for a larger screw or get another distributor. But yeah you'll want to narrow it down a bit first, check the transmission mount, torque arm mount, etc...

 

Thanks for the help.