it has the f4 block, has 160k on it i bought this car not even a week ago, and im about ready to set it on fire and let it burn to the ground, when i got it it ran fine, until it warmed up, then it did its little song and dance and wouldnt start back up easily, every time i would let off to shift it backfired, CEL light has been on, got it to flash at me, pulled codes for an 02 sensor, CYL position sensor, TPS sensor crank angle and MAP sensor, it had basically no exhaust on it, and the valve cover just dumped oil into the exhaust. changed the valve cover gasket, cleaned out the spark plug sleeves, put new wires and NGK platinum plugs in it gapped to .44, as recommended in the Haynes manual, that stopped the backfiring for the most part, took off the cap to inspect under it and discovered what appeared to be metal shavings which is all over the magnet under the cap, the ignition coil spring had some corrosion on it, so i cleaned that up, not much improvement. so i moved on to the TPS, put it on and it wanted to finally idle, discovered that the sensor needed timed, so i looked up the process and timed it, then pulled the BACK UP fuse to clear the CEL, the light stayed off for about a minute and then came on, i also put a generic AEM 2.5in intake on it because i picked it up for 10 bucks with a new filter on it, so i pulled the codes from the CEL and its only flashing a code 9 (CYL POSITION), checked resistance and voltage to the plug and its all within spec. pulled the plugs and they were jet black, cleaned them up a bit and had the exhaust patched, no more exhaust leak, cleared the CEL, ran some seafoam through it and fogged it with some seafoam as well, small improvement but the CEL comes back on after about a minute with the same code 9, put new NGK platinums in it, had some improvement, took it on the freeway and pegged it to 5 grand before shifting to see if it would cut out, it was fine, then cruising back to the house it would tap out at 3500 no matter how hard i hit the gas, then sitting at a red light it stalled, tried to start back up and it just cranks, when it fired it fired about 3 times and died, so i held the gas half down, it started and stalled immediately and the engine kicked back almost as if the timing were off, finally started back up so i cruised home, while holding a steady rpm it will sputter and occasionally it will just pop and jerk really hard, i also get a very strong exhaust and gas smell filling the car AFTER the CEL light comes on, my dad thinks its the o2 sensor but i dont think it is since the code isnt an o2 sensor, we turned the distributor toward the car and it seemed to improve a bit, but i was still getting a rich exhaust scent, so i turned the distributor toward the front of the car and it didnt really want to run, so i put it back to far position toward the car which i believe is advanced, cleared the CEL again and still getting a code 9, i was told to replace the IAC, so i put a new one on, no improvement so i cleaned up the screen on the old one and put it back in, also when i put the TPS on i cleaned the throttle body up real nice, i was reading around and am thinking it could be the timing belt off a tooth, but i also ready that the intake would throw off the air fuel ratio, im absolutely lost and dont know what to do next.

 

Lots of info there and it's kind of hard to follow, but one thing I get is that it appears to be running rich. Pull the vacuum line on the fuel pressure regulator and check for gas. If there is gas, then the regulator is bad. If no gas, check your fuel pressure. Typically, it should be 40ish psi. I don't have the specs for a '91, but I'm guessing someone here does.

 

Code 9 keeps returning. That is the cylinder position sensor that is inside of the distributor.

Now this problem can be the distributor, the wiring, or the ECU. If the sensor is the problem, the whole distributor needs replaced.

It is always best to start simple. There is an important ground bolted to the thermostat housing. Remove that ground and clean the bolt and eyelet with a wire brush or sand paper. Clear the codes, then drive and see if the problem is fixed.

You posted a lot of information, and I have a few questions. You said there were metal shavings in the distributor. Did you figure out why there was metal shavings in there?

 

I kinda just rambled on i see, as far as the metal shavings go i have no idea where they came from, upon inspecting the distributor nothing appears to be shaven down, while it was at the exhaust shop i was looking under it real good and did notice the main battery ground end was stripped and corroded real bad, as far as the regulator goes i pulled the vacuum line and had no fuel spraying out, however the fuel psi should be no higher than 38 psi, i dont have the tool to screw into the fuel rail that would clip into the fuel psi gauge. But the more i thought about it the more i wondered if it was possible the timing is off a tooth on the belts and the distributor was played with to try and compensate for it, im trying to get a general direction before i dump more money into it