For about a week now.....my 91 SE Auto somtimes will act like I have the automatic trans switch in POWER mode even when its not....I'll be driving and from one light to the next it shifts just like it does when I have it in POWER. I flipped the switch to COMFORT mode and it still shifts at higher rpms Also when this happens the engine idles high(1200rpms). Trans was rebuilt this past Feb., it's strong and healthy. TPS?

 

anyone?........

 

I don'r really know but bad grounds affect the trans shifting.

 

does the green light go on for comfort?

 

Yes......the switch does work ok

 

I would start with a TPS (or TPS connector) if the shifts still feel normal, if the shifts are very soft, then start looking for grounding issues.

 

Also check the fluid level, and the coolant temp sensor. Make sure its not bad or doesnt have corrosion on the connector.

~Alex

 

Shifts still feel firm....The valve body was modified on the rebuild and still feels good.

I'll check that coolant temp sensor today. That's the one that's right on coolant neck where upper radiator hose enters engine right? Trans fluid and level is fine.

 

that thats it, you want to check the one with 2 wires. mine has alot of corrosion on it and I couldnt get it clean. so I bent it and it helped but I need to put on the connector I got from my parts car, its perfectly clean. Also use some connector grese to keep it from corroding.

A bad coolant sensor/bad connection will cause a strange idle, on my manual it would constantly bounce the idle from 1600rpm-2200rpm. It was insanely annoying. I know it makes autos do funny things.

~Alex

 

Now that you say that....Lately I have noticed a high idle sometimes that won't go down. Then all of a sudden it will go back to normal ~750. I'll see what it looks like.

 

Checked the coolant temp connector and it does have a little corrosion. I used tiny screwdriver and scraped it as good as I could. A few of my injector connectors have this too but they all work perfect.