I thought I should write an update on the pinging/timing issue with my 94GT. I know that pinging issue is common in these cars since a number of sensors/setting can cause this. Over the last couple of years I ended up replacing ICM, coil, dizzy cap & rotor, plugs and wires, injectors, IAT, MAF, HB, IAC, TPS, timing chain, cleaned ALL the electrical ground connections but did not solve the issue. I know that there are ways to check these sensors without replacing them I decided to replace them just to be sure. Just to make it fun, recently it went through a no start (but cranks) phase which turned out to be a bad PIP. Along with all these, it developed a lifter knock and in response I replaced the leaking rear main seal. To make it more fun my oil pressure gauge needle stated to fluctuate like crazy even after replacing the seal and oil pressure sensor. I though my oil pump was going bad and causing low oil pressure causing my lifters to act up. I thought this can cause some timing issue. However, it turned out that the instrument panel was acting up and there was a connection issue in the circuit which was corrected by a visit to a local junk yard. In the mean time my local mechanic "solved" the pinging problem by setting the timing at 21degereed BTDC! To my astonishment the engine was still running with that.
Yesterday, I think I finally solved the problem with pinging, lack of power, unstable timing and engine running fuel rich. I feel like a burden has been lifted finally. It turned out to be the O2 sensors. I set the timing at 11degrees and put 87 gas in it (before I was putting 93 just to make it drivable) and drove it in open throttle up hill in 4th and it did not ping for the first time! I feel like celebrating but I am being cautious. I think this car can pull another trick on me any time.
