Originally Posted by gladesteen
I pulled the PCM out and cleaned the motherboard up. It was nasty on the backside. I ended up removing the whole board and then used alcohol and q-tips to clean it up.
Put it all back together and it ran fine for awhile. I took it for a drive to get more electrical cleaner and while i was at autozone it started doing that "freak out" thing where the engine/lights/alarm chime for 1 second happens. After it stumbled and came back i let it sit idling. The RPM'* were searching going up and down. Sounds like TPS to me, but its already been changed out. Guess i will clean up the TPS and IAC again.....see what happens.
If this still keeps happening, i guess ill bite the bullet and go get a new PCM.
You have mounted a brute force attack of parts, money, and time at this problem. And that is truly admirable. But let'* step back for a moment and look at this from a problem solving standpoint.
I'm assuming you can't get the code from the check engine light? If so, it is likely because the '95 is an OBD hybrid. You need a scantool which has an OBDII ('96 and later) connector, but can read OBDI ('95 and older) data.
We're skrewed for diagnosis without those error codes. Solely for my '95, I have the first release of the Actron CP9145 with the OBDII cable. This can pick up both OBDI and OBDII codes. The problem with it is operating data displayed for OBDII cars is way limited. It leaves out fundamental things you need to know, like charging system voltage (and KR). Later releases of it are on ebay, but are only worth it if they have widely expanded the amount of data for OBDII cars.
I'm not sure the error codes would indicate the exact source of the problem, but it would definitely give us symptoms of where and how the failure first takes place.
For sake of discussion, we'll put aside the error codes and PCM for the moment.
It is highly unlikely that an air or fuel problem would cause your dash gages to all go wacky. They would only cause it because they failed and took down the electricals and electronics. So, I have one more guess for you before the PCM.
If you are sure your charging system is good (particularly the ground cable from the battery'* positive terminal to the ground connection on the bottom of the engine block) then the dash board is screaming then you have an electrical/electronics problem outside of the charging circuit.
The usual suspect is the ground bus connection under the plastic rail covers at the foot of the door openings on the driver and front passenger side. The driver side is the most frequent culprit. The wires from front to back and back to front connect there in a bus, and the bus is connected to the metal grounding plate. Over time, water gets in there and the plate corrodes or connections do.
The plate should be sanded/ground back to bare metal and each individual connection should be pulled and sprayed with a contact cleaner.
This is not wasted time, even if it isn't the cure. With that ground conjunction, it'* not a matter of "if " it'* going to cause a bizarre problem, it'* a matter of "when".
This is my best guess without error codes. Next is the PCM. Plus with this hitting electricals/electronics, you don't know what that PCM is thinking right now, or what state it is in. Consistent in design, if you have an engine light problem... and that problem is a threat to damage the engine or tranny... the PCM accesses different programming and tables to prevent you from further damaging the car. For example, if the trans has problems shifting between 3rd gear and overdrive, the PCM eliminates overdrive from the shift pattern.
We really need those codes.
I'll check back, while I try to learn more about our fuel systems, and WTH is wrong with mine.