Engine dies during coasting

[stolher]

I will try to explain this to the best of my ability, if need be I'll take some video later on.

(AC off) During start up the engine will shoot up to about 1500 rpm then drop down to about 200 rpm and level out at normal idle. As I am driving everything is kosher. but when the time comes to stop if I do not down shift and just push in the clutch the rpm will fall to about 200 rpm and then level off at idle or sometimes even die.

(AC on) if I start the car with AC on the car will start and die. If I turn the AC on at idle and give it a little gas she will keep running but at 500 rpm. If I go to stop with the AC and depress the clutch the engine will die every time with out exception. If I down shift and coast until 1000 rpm then she will sometimes hold out and idle.

I just replaced the IAC and the pressure sensor on the AC accumulator/dryer, with absolutely no change. I was told it may be due to turbulant air in my RAI so I removed to cover. And the car was recently tuned by XXX in P-cola, FL. I have searched and searched and searched and have netted nothing. Does anyone have any tips?

 

[hyelife2]

Have you tried cleaning the MAF?
FWIW I had a similar issue and cleaning it out fixed it for me.

 

[Mystic03]

alternator...?

 

[SVTwhore]

I would try the things above and also try giving your tuner a call. My car was doing something similar recently as well. Not sure about the whole AC part as I never really use it so I can't say for sure. Anyways, mine was falling on it's face and dying because the tune was off a little. Did some data logging and went back to the tuner, he straightened out a couple of things and it's been perfect since.

 

[stolher]

Have you tried cleaning the MAF?
FWIW I had a similar issue and cleaning it out fixed it for me.

done, twice actually to ensure I did it right!

alternator...?

New and upgraded

I would try the things above and also try giving your tuner a call. My car was doing something similar recently as well. Not sure about the whole AC part as I never really use it so I can't say for sure. Anyways, mine was falling on it's face and dying because the tune was off a little. Did some data logging and went back to the tuner, he straightened out a couple of things and it's been perfect since.

I'll have to give Brad a call and see if we can do some data logging.

 

[silverserpant]

I had a the same problem and found the blower/tb I installed had the tb set screw backed right off and left it up to the IAC to try and compensate and hold idle, after I reset the screw to hold the blades at desired idle I no longer get the rpm droop or stall when I let off. plagued me for a long time trying to find the droop, stall and choppy idle.

 

[hotcobra03]

after 327,000 miles the only electrial part i have changed were the coils @300k..

o before changing coils i had your exact issue....

 

[stolher]

I'll look into both. Thanks for the ideas. I also noticed that if I coast in gear my fuel pressure will rise to 30psi. If I hit the gas she will choke a bit then drop down to 10-20 psi and act normal

Edit. Just checked the throttle body set screw. It is about half way in. I'll have to check the manual and see how to set it

 

[silverserpant]

Sounds like you have a bad or weak pump. Should be at around 39 psi cruising

 

[stolher]

Shoot really?!

 

[stolher]

Maybe I ought to upgrade while I'm in the tank

 

[silverserpant]

I just used a feeler gauge till it touched the stop, hasent had the stall yet since adjustment.