SPCMarty

Haha, I got my car to go fast in. I drive 40 in a 30 just to avoid the jerking motion.

Bibo1985

Convenient how most speed limits below 55MPH are at usually at a good shift point isn't it? I've found out the hard way to run it in a lower gear, sure your running higher RPM's, but I trust the engine to hold up a whole lot more than I trust the tranny.
I've yet to check my fuel pressure to be sure if that's bad, but today I found a few pinhole leaks in the vac line to the brak booster. Taped em up (temprorarily) and it got a lot better. We could end up having 2 entirely different causes, but one of the bitchiest things to track down is a vac leak, cuz there's so many places it can leak from.
Hope ya get it figured out soon!

SPCMarty

How would you find such small leaks?
I doubt its the tranny shifting, it jerks between 30 and 38. Haven't tested cruising slower.

Bibo1985

You can test for intake leaks with Carb cleaner, spray it around the intake gasket with the truck running, and if it idles up, then you just found your leak.
For the vac leaks I usually go by ear with the engine running and start to touch around where the vac fittings attach, when you hear the hissing/sucking sound stop, then there's your leak.
Others here can tell you about using a vacuum gauge and all that, but I've never used one before.
A few good starting points to check; brake booster vac line, the two lines coming out of the throttle body and the fitting they attach to, the line going to your vac canister (lil black box on frame, passengar side between serp belt & radiator) and the line to your MAP. I found those are EASY to knock looe/dry rot