Well, it finally got warm enough to work on this sucker. Set the timing and the shudder is reduced, but still there.

 

have you checked and cleaned the maf, or checked that the tps is adjusted correctly. either of those could cause an issue that would produce a shudder. since the engine was missing badly before, the catalytic converter may have broken up and lodged sideways in the exhaust. that would cause a shudder and a lack of power as well.

 

I haven't checked the MAF yet. The previous owner changed out the TPS, so I doubt thats it. I did find that I had the timing set wrong, I had it at 0* BTDC and I found that it should be at 6* BTDC. Setting it there gave it a TON more power and reduced the shudder by 50%.

I also have a big lead in finding out that my knock sensor wires have pretty much crumbled where it attaches. Going to try disconnecting it and see if the shudder goes away.

 

may bad, 89 wouldnt have a maf but a map. could still be a problem, but i think they were slightly more reliable. have you checked the driveline for loose parts? maybe a tire out of balance?

 

It has a MAF, it's in the intake tube. It shudders in park. I took it out for a bit of road tuning, heard some pinging, finally found the area on the timing with the least shudder/pinging and the most power. Definitely seems like I have the problem nearly nailed down now. Going to try a bit more fine tuning and I will post back with the results.

 

did you fix the wiring on the knock sensor? that will help rid the ping. i had the same issue with that on my tpi, the wiring fell apart. the ping was only noticeable above 3/4 throttle, but fixing the knock sensor cured it. if you come up with nothing still, you might want to do a compression test and probably adjust the valves. even hydraulic lifters need to be adjusted every once in a while

 

THEY DO??? Unless lifter goes bad why would it need adjustment?

 

ive had lifters stick about half way down. just enough that it didnt tap loudly, but it was causing an issue. might be something to look into. and you cant rule out someone else who may have had it apart before and didnt do it correctly

 

Found it finally. Several fuel injector clips weren't making good contact, changed em out and it fixed it.

 

thats good to hear. now go out and drive. see if you can meet up with the ricekiller group in dfw, theyre pretty big down there