Well Last Night I Started My New 383 Up And Theres One Problem Its Idling Is Way Off It Jumps From 1-3k Then Give It A Little More Time Then Engine Will Drop Below 1k And Die And Some How If You Disconnect The Maf It Idles Fine For About 5-10 Min Then All Of A Sudden Jumps To 3k And Stays There Any Ideas?? List Of Mods On What I Think It Could Be Below I Dont Know....

*255lb Walbro Fuel Pump (not Installed Yet Wanted To Test It Stock)
*38lb Injectors Racetronics
*58mm Throttle Body

 

Vaccuum leak?

 

Yep check for vacuum leaks.

 

Did you get those injectors tuned? if you havn't tuned for those BIG injectors then you might wanna have that done before you try to run it anymore.

 

yea its tuned all right by brian from pcmforless i was thinking but i could be wrong but can it be from me not sloting the holes for the throttle body??

 

You talking on the intake?
YOu don't really change much for the throttle body in a tune, YOur mass air reads how much is moving through and then adjusts your injectors for that air so that shouldn't be a problem other than you are not getting max hp without boring out your intake to fit the tb. Wile its running fine when you unplug your mas air unit your pcm is still in whats called closed loop. so it will assume only certain criteria for the engine to run, when it hits open loop it will then read all your sensors and then start adjusting things to make the engine run for the readings that its takeing, what mass air are you using? I had this similar problem with my car, I had and SLP Z06 mass air that only Ed
Write would tune no body else had the tables to make it run right and I had changed to 30# svo injectors and i tried to tune myself using factory tables on the mass air and it wouldn't work and Ed wouldn't release the data to me for the mass air, I had to pay him for a re-tune on the mass air.

 

well lloyd ported my stock intake to fit a 58mm so doubt that can be it as far as mass air flow im using the stock one i didnt think i had to change it but if thats what it is then ill buy a new one

 

you don't need to change your mass air, I was just checking on it since I had a close problem to yours and thats what my problem was but if you have the stock on then the flow tables will be the stock ones. What were you talking about slotting holes for the 58mm tb?
I am not ruling out the possibility of a vacuum leak it would have to be a big vacuum leak though to kill it. check all your electrical connections on your tb and intake as well and make sure you don't have a loose one.

 

meaning on the tps im not too sure about it but thats one of the solutions that i have been told thanks for the info though any othere ideas it could be ?

 

Not sure about that "slotting" idea! I had a 58mm holley and didn't have to change anything but the intake holes. I wouldn't go modifying that piece or you might have to get a new one. do you have a scan tool? if so you could check the readings on the tps in relation to idle. I don't remember what voltage its supposed to be at at idle or at wot but if you have a shop manual it will tell you or i could look it up when I get home from work.

 

My younger Brother had the same problem... The exact same problem after his 350 ci. rebuild, stage 3 lt4 heads and cc306, He had a intake gasket leak. It is fixed now and running like a raped ape. What kind of exhaust do you have, are you able to hear the motor good or is it too loud? We could not hear his motor over the exhaust.
Steve

 

A friend of mine fried his MAF, data master showed 287gps at idle, may look there

Good luck