Possessed 89 PA

Hello again. My PA has me stumped on several issues, but first here is the list of new parts as of the last 4k miles (as long as I've had the car)

EGR valve off 45k engine
new CTS sensor
plugs and wires
O2 sensor
battery
PCV valve
Air filter
fuel filter
vacuum lines rubber connectors
chevron techron ran through fuel
marvel mystery oil ran in crankcase
steering column

Ok, now my issues:

1. After running the car for a while on the interstate, my car jerks and my speedo, trip, cruise, and odo quit. My SES light comes on. After I slow down or stop they work again and the SES light goes off. Doesn't store codes initially.

2. After a couple rounds of my guagues dying, my ses light will give a code 63 (egr valve) and once a code 31 (grounded park neutral switch). Code will randomly clear itself after a few days of showing up.

3. If I run my car at WOT (wide open throttle, right?) when it hasn't warmed up to operating temps, it will shift very roughly from drive into park or reverse when I stop in my driveway, parking spot, etc..

4. When first started, the car will idle strange--it will idle high and low randomly and I can hear a whistling noise (but is not constant--changes w/ idle). Also, sometimes when I put my car from drive to park after being at operating temps it will idle very high in park untill I shut off the car. Starts up just fine afterwards.

I changed out the EGR and the CTS (coolant temp sensor) after the first couple of times of cleanin up my egr w/ gobs of carb cleaner. The only thing that this has seemed to have done is to prolong the occurance of the engine jerking and my guagues quitting, but it still happens.

Suggestions I've Had:

1. Bad ECM causing the random code loss. I have one on my wrecked Olds that I'm gonig to put on in a few minutes.

2. Bad speed sensor. I'm not getting a code for it though but it would explain the random quitting of guages, but not for the jerking.

3. The whistling is probably a vacuum leak but I cant find the sucker...all my hoses are new or are plastic.

4. Transmission is dying.


I think I may have more than one problem but I thought I would try you guys to get some help with at least narrowing down my possibilities... I'm longwinded but I guess one post is better than three or four.

Thanks for help!!!

Just got in from replacing the ECM. So far no codes have shown up and no random gauge quitting, but I only drove on the insterstate for a few miles... Seems to run a lot better now.

The ecm that was in the PA says "remanufactured by GM corp. APTF 1-90" on it. So I assume that it went bad and then repaired not too long after the car was built.

Anyway, it still has a high idle when in park after running at WOT...