so i got the 89 gtu na working like a champ after a i found a vacuu leak in the lim. now after 2 days of not driving it. it started runing bad. it could barely hold an idle and the whole car shakes. i adjusted the tps, adjusted timing to 5*atdc, but it still running and drives like crap. How do i know if my motor went bad. i'm going to pull the spark plugs tomorrow to see if they are fouled, but what can cause her to run bad without showing gradual symptoms of something going wrong?? someone pls help. thanks in advance.

 

I would check the coil packs , it sounds like the fuel is not burning corectly , even setting the timing would not help , also take a compression test, take out the check valve on a
regular comp. tester and you should be able to see the reading for each side of the rotor
also check the spark plug cables , one one thing the rubber o rings to the fuel injetors could be leaking still giving you a vaccum leak , if none of this works please let me know
always willing to help

 

Make sure you have a good spark. If one leading plug fires, so will the other one (they are two sides of the same coil). Make sure there are not any huge vacuum leaks.

After that, compression test.

You may also have the ultra-rare stuck fuel injector. If they stick open, they produce a symptom similar to a blown engine. But do a compression test first.

Oh, and see this page: http://www.aaroncake.net/rx-7/blown.htm

 

If you took off the intake pipe, make sure you plugged in the AFM and the other air lines when you reinstalled it.

 

thanks guys, i'll try those out. just one question. im not sure how to do the compression test and how do i know if the injectors are stuck open?

 

so i tested the resistace on the tps(full and narrow range) and the closed positon resistance is above 4k. the tps being bad is most likely the reason my fc is running like this right??

 

Did you follow the factory proceedure for checking the TPS? It must be done with the car fully warmed up. It should show 1K with the throttle closed.

A quick compression check is easy as described in the page that I linked to.