i have a 93 bonny and while driving the rpm seems to look a little high but the engine so ok but when i stop the rpm drop under 1 and it feels like it wanna shut off and sometimes it actually does but when its and park it runs ok i just had a full tune up a week ago

What was all done for the tune up? First thing you will want to check is for vacuum leaks. Also try taking a spray bottle filled with water and mist the plugs, wires, and coils while the engine is running. Then shut off the lights and watch for blue flashes. These are grounds and will need to be fixed.

could it be my tp sensor

That is a possibility, here'* a test for it. https://www.gmforum.com/t279319/

hmm

sounds a bit like my dads problem he just fixed on his 94 Olds

His was a bad EGR valve.

how would you kno if the egr valve is bad

The EGR is supposed to be closed at idle, but if it is stuck partly open then idle quality will be poor: slow and rough (uneven) and you may have poor gas mileage.
The EGR controls the exhaust gas flow into the intake.

To test if the EGR is stuck:
1. On a cold engine start the car and let it idle.
2. If the EGR valve gets hot right away it is pulling in hot exhaust gas when it should be shut.

Too much EGR flow tends to weaken combustion, causing the engine to run roughly or stop. With too much EGR flow at idle, cruise, or cold operation, any of the following conditions may happen:
* Engine stops after cold start.
* Engine stops at idle after deceleration.
* Car surges during cruise.
* Rough idle.
If the EGR valve should stay open all of the time, the engine may not idle.

Too little or no EGR flow allows combustion temperatures to get too high during acceleration and load conditions. This could cause:
* Spark knock (detonation).
* Engine overheating.
* Emission test failure.

yesturday i drove my 93 bonneville 3.8 and as i mention before it seems as if its going to cut off whyll stoping and when im looking at the rpm hand will stoping it seems like the rpm hand is going up and down(its like u driving forward and you and u doing 60 u kno how when driving the rpm shows when u going from 1 to 2 gear but and my case its like when im stoping i can see the rpm hand down shiftin from 2nd the 1st .and while driving the car drives kinda rough..

do u think that can be my problem my car stalls sometimes and maybe even cut off while stoping the rpm drops under 1 and just goes out while accelerating from stop

Please continue this in your original post.

Thank You


merged with:

https://www.gmforum.com/t280157/