Hi Guys,
Getting close to the end of my restore on my 91 GTA. It has the TPI 350. It had an auto and I swapped in a T5. Now what is left is an engine vibration. It is the worst between 1200 and 2000rpm's. It occurs in all situations(driving, natural..ect.). On the freeway engine at 1500rpm's you can feel the whole car vibrate in and out, kinda feels like a bad driveline but changes when I push in the clutch. Now for a little history.


Found the car in a field infested with mice. They chewed through most of the wiring on the engine. Lots of repairs to the harness.


New fuel pump(was bad when I bought it). Suspect for the reason it was parked.


At this point the car was running and semi drivable but had a minor rod knock. (might have been the other reason it was parked).


Installed new injectors, EGR valve, timing chain and lifters.(wasn't sure on the rod knock)


Did the T5 swap. Used flywheel, used trans, new clutch kit.


At this point I knew I had a rod knock so I had my mechanic install a new crank. Rod knock gone. When I got the car back it surged at idle and had the vibration(can't recall if it was there before, didn't drive it much). Sometimes the surge would kill the car at a light. When I returned to the mechanic with a rear main seal leak, he started looking for the issue. Ran it with the tranny out and it still vibrated. I had him install a new flywheel just in case that was the issue. Swapped the O2 sensor and the IAC. Idles better and doesn't die, but still has the vibration and a slight surge. I took the car home and swapped the distributor, coil, cap, rotor, plugs and wires with spares I had laying around. Same problem(not as prominent but still there and pretty bad between the 12 and 2k marks. Sorry for being so long winded but I am at the end of my knowledge and a bit frustrated.


Any thought would be appreciated. Also, no vacuum leaks that me and my mechanic can find.


Thanks

 

Maybe a 305 crank was installed. Physically the same but balanced different

 

I'll check that out with the mechanic.


Thanks