Help!!!!

[spoolin85]

When I step on the gas the car has a bad hesitation. It idles really low, and sometimes irratic. When the car is cold it usually run great,, The hessitation is almost not noticed. Now when cold its acting up as well. It feels like there is a miss off idle, but now when at a cruising speed. Every now and then if im idleing in gear and I hit the gas a little( spike it really quick) the car feels like its gonna die or now and then will die out. It will start right back up. The last couple days when I start t when its cold it dies out right away,, then it restarts and stays running. I just rebuilt the motor and before I was having this problem,,, and now its happening again. The car also feels verysluggish. After the rebuild it was fine for a while then it started acting up again. There are no codes. I replaced the tps once and it ran the same,, and it is set. Cam sensor is new and set. The car also boosts very fast,, It seems like it is overboosting to 18psi right away when i give about 1/2 to 3/4 throttle. I was thinking the mass airflow sensor.. The car sucks alot of air when cold once warmed up it isnt that noticable. PLEASE HELP!!!!

 

[crazygn]

Did you tap on the maf when it was running to see if it dies out or run the same, or unplug it and see what happens at idle. Also i would check the plug wires and plugs i have had bad luck with both , I had a plug go bad not to long ago and the thing did not even want to run , and they were only about a week old.

 

[spoolin85]

I tapped on the maf, but it stayed the same. When it is unplugged the car ran and seemed to idle better but threw a service engine soon light. Ive put on 3 sets of wires, and its always done the same thing, had a big hesitation off the line

 

[spoolin85]

ttt

 

[Buick From Hell]

Fuel pressure okay? How's the fuel filter? Injectors?

 

[spoolin85]

presure seems to be fine. Injectors are new. fuel filters been changed since its been doing this like 3 times.

 

[b4black]

Vacuum leak.

How many "Hg are you pulling at idle?

 

[spoolin85]

Im at around 12 on my vacuum/boost gauge when Idleing. When you here alot of air sucking that is when the car runs best. It feels likethe idle is low. The car has night and day differences. Some time the power is unbeleivable, other times it does not exsist. Every once and awhile when I start it, IT runs really rough and wants to die or does now and then.

 

[crazygn]

Did you set your tps and iac, do you have a scan tool to use to see whats up. Maybe you should check your o2 sensor to.

 

[b4black]

Originally posted by spoolin85
Im at around 12 on my vacuum/boost gauge when Idleing.

Sounds low to me. It should be ~15, IMO. I would get a vacuum line diagram and start checking EVERYTHING. Not just the lines, but make sure sensors and such aren't leaking either.