After the first run at an autocross today, I was heading back to the paddock, and the motor felt *really* rough on idle. Get back and pop the hood, and the motor is shaking big time at idle. The tach is steady at about 800 RPM.

I let the motor cool down a bit, checked all the connectors and vacuume lines and everything I could see looked fine. If it's idleing at 1K and up, the motor's smooth - on the drive home it pulled well.

I let it cool again in the carport and warmed it up again, and same problem - motor's doing the samba in the engine bay. At 1K and up, everything sounds and feels fine.

I have not had a chance to do a compression test yet.

SO: Loose line? Popped seal? Broken motor mount?

Any ideas would be appreciated.

Z

 

If nothing is smoking it is not a seal could be something with fuel or timing i would get a timing gun and check that out. -Gabe

 

My money is on the idea that you aren't firing right anymore.

You threw a plug wire or igniter.

But im gonna toss in the ever popular vaccum hose, just for good measure.

Im ignoring the idea you "broke" a internal part.
Its just too bad to consider.

So, clearly that cant be what you did.

 

Compression tested OK. (whew!)

When I took out the trailing plugs, the one for rotor 1 (front of motor) looked like it was fouled a bit compaired to the one from the other rotor - had more carbon up the thread of the screw than did the second. Changed the trailing plugs and all wires and the same idle problem happened - not as bad as before, but still shaking the whole car.

I could not get the leading plug off (way too tight), so I'm going to let the motor cool overnight and try again tomorrow.

If it still will not play nice and come out, then it's back to the shop that did the rebuild and put that SOB in in the first place and let them worry about it.