I had to replace the transmission support bushing and now the car runs rough. It sounds like there is a vacuum or piston noise (in and out kind of noise)in the front of the car, it idles poorly, runs rough when accelerating, and seems to lack power.

While replacing the bushing, I didn't mess with the engine, but I swapped out half the exhaust with a used exhaust in better shape from a guy who was doing a Chevy V8 swap. I swapped out from the second cat to the back of the car on both sides. The exhaust seemed to be in very good shape. Could this be the problem?

Any ideas would be appreciated. Someone in another post mentioned a vacuum hose that goes from the intake to the trunk - any clarification about this would be appreciated.

Thanks!

 

At the back of the engine there is a 1" aluminum vacuum balance tube. The vacuum hose to the trunk mounted ECU is attached to the tube, almost dead center, down low. Make sure it's attached. It runs along the underside of the car....although I can't remember the exact route it takes. You might have knocked it loose or damaged it. Not likely, but maybe.

It might be easier to just go to the trunk and pull the hose off the ECU and see if you're getting vacuum with the engine running. The ECU is to the right of the battery, behind (as I recall) a plastic or carpeted cover.

Cheers
DD

 

Thanks Doug. I'll try to take a look at it this weekend and report back with any findings. I suspect the "new" exhaust I put on is clogged. If the vacuum balance tube isn't the issue, i'll probably pull the "new" exhaust and put back on the old exhaust, leaks and all, and see if it runs smoother.

 

Checked the vacuum line in the trunk, going into the ECU, and it was pulling good vacuum, so that' s not it. Guess I gotta put it back up on jacks and swap out the exhaust and hope that fixes the problem.

 

Doug is on it! Too bad that wasn't it.

Have a look at the vacuum modulator hose too. Easiest way is the same sort of test, pull the hose off the back of the RH intake manifold and suck. If it holds vacuum, that doesn't suck either.

 

Thanks Ohio- checked that and it's holding vacuum. Turned out the "new" used exhaust mufflers were plugged. Put the originals back in and it runs MUCH better. Thanks for the help.