I have an 87 SE, all stock except for the bonez superflo kit. Over the course of the last month or two, I've noticed the motor shuddering, getting rougher and rougher slowly over the course of time. The RPM's are at 750 and haven't changed over the last year.

I changed my plugs and wires today (NGK's for everything), and that didn't help. I checked for loose vacuum hoses, wires, etc and everything looked good.

I did notice, however, that by pushing down on the top of the engine with a little force stopped the engine shuddering. Could I possibly have a loose motor mount or one going bad?

Thanx in advance for any advice.

 

OOPS! Wrong thread! Sorry bout that...

 

Sounds like an intake manifold gasket is bad. If you have a vacuum leak it will idle rough. Up and down. Also since you push down and it goes away leads me to believe your closing the gap and temporarily curing the leak.