so i just got the car home from the mechanics he cant figure it out

put in another fuel pump car runs idles fine if throttle is kept at 900-1200rmp

can rev upto full rpm sounds like it has a bit of a gurgle
but doesnt studder unless i go from no throttle to 1/2 or more quickly

exhaust is dripping blackish water leading me to believe its running rich

when driving down the street i can give it only 1/8th throttle anymore and i start to lost power and studder and putt
but if i give to half throttle in overdrive the transmission changes into overdrive drives really ruff and i go back to 1/8th throttle it stays in overdrive and starts to put up good but if i give it anymore the 1/8 is start losing power fast

and if it goes into a lower gear in (D) (overdrive) the front end of the car starts to jump on the road a bit

opened the hood took a listen and i can hear a small whistle and when i give is a semi-quick shot of gas to maybe 3-3500 rpm i can hear a ( psssssssssssss) almost like a blowoff valve sound like im losing air and that probly y it running rich and liked ****

my mechanic took a cigarette and moved it around the throttle body and intake manifold it see if it was sucking or blowing air and it doesnt seem like it

checked the vac hoses and vac fitting and o ring the goes to fuel pressure regulator transmission and purge and it seems fine aswell


Where else can i be losing air?
or any idea of potential causes ?

thanks for everyone'* help so far

Has he replaced your fuel pressure regulator? There is vacuum lines that go down to the Charcoal canister that my be disconnected or broken.

yes i have changed the fuel pressure regulator i had the car start spudder for a min the stall and it sounded like that cylinder were start full of exhaust im now thinking its a blocked shut catalydic converter i drilled six holes in the cat and the car start ran a drove home im gonn change cat tomorrow off my parts carwill update later

Hope it works for you. Let us know.

too me it sounds like the motor was running too rich, flooding the cylinders while trying to start the car and soaking the spark plugs. I would check the spark plugs and see if they're wet due to rich mixture, if they are test the MAF sensor as mention above.
If the motor is having trouble starting, its probably because the cylinders are flooded and it hard for the plugs to ignite since they get only around 10v without the alternators help. Try Pressing the gas pedal all the way back "disengaging the fuel pump" and try cranking to try burning off the access fuel in the system (earned this trick here in the forum ) then turn the key to the off position for few seconds and try cranking her again.
This use to happen to me in hot/warm climates.


BTW i also get that blow off valve sound for some reason when you give it a quick jerk of gas in the engine compartment. :/

the blow off valve sound your hearing could just be belt slip.

How old is the belt? look cracked at all?

belt is 4 months old


plugs and cables are 3 mths old

used ngk plug wires and ac delco plugs ( was told premimum plug upset the bonnieville)

ive cleaned the maf sensor myself to see if thats was causing it and i took it to gm about 11mths ago and they charged my $45 and said they cleaned the MAF

about to go do the cat in an hour so well so how i far im gonna test the coil pack for voltage if i can get my hand on a volt metre i guess i should be testing the MAF and Coil packs

well the car is running and during a srtart up correct?

the sound was comming from the intake air box.

to check the MAF this is what i did: https://www.gmforum.com/t279437/
With the coil packs i would unplug 1 cable at a time from the coil While the car is running and see if theres any change, if no change while you unplug 1 by1 then you just found a bad coil.

BTW did you gap the spark plugs?
Im using premium ACdelco plugs and haven't had much of an issue. FYI