C4 Intermitent Problem When Warm (please Help!!!)
Thread Starter
Instructor
Joined: Feb 2008
Posts: 170
Likes: 0
From: hopatcong NJ
C4 Intermitent Problem When Warm (please Help!!!)
Hey guys, im sure some of you will read this again as i have posted in different forum, all the feedback was great but unfortunity im still having an issue and im very frustrated, so here is the deal, i have a 1994 lt1 and this problem only happens when the car is warm, never ever does it cold, car starts up fine, then rpm's drop and is either starving or lacking fuel, after about 20 secs it stop and car drives perfect, never does it at a light only at intial start when warm..and the weird part is sometimes its fine...im pretty sure this is a fuel issue not a tune-up/elec issue, some have said fuel presure reg which dont think that it is cause would do all the time, maybe 02 sensor or a leaking injector? any way it could be this????i need some feedback from you experts, i have replaced coolant sensor that feeds computer, i have cleaned TB, i have done top engine clean, fuel injector clean in fuel, dont know what the next thing to check, please help this is driving me nuts!!!! 
Burning Brakes
Joined: Apr 2006
Posts: 765
Likes: 0
From: Houston Texas
Are you saying that it doesn't do it ever when starting cold, but starts up fine when warm, but does this little thingy (sometimes) when in (closed loop)?
Or, are you saying you start it cold and then drive until it is warmed up (closed loop) and it doesn't do it at a light or stop sign (idle). Then when you cut it off warm and when re-starting it while still warm, it does it sometimes?
The computer uses different air/fuel mixture tables in open/closed loop. Have you cleaned the MSF/IAC sensors or checked their connections? Use some electronic spray cleaner on the sensors and connections. The parts houses have it if you don't already have some.
Or, are you saying you start it cold and then drive until it is warmed up (closed loop) and it doesn't do it at a light or stop sign (idle). Then when you cut it off warm and when re-starting it while still warm, it does it sometimes?
The computer uses different air/fuel mixture tables in open/closed loop. Have you cleaned the MSF/IAC sensors or checked their connections? Use some electronic spray cleaner on the sensors and connections. The parts houses have it if you don't already have some.
Thread Starter
Instructor
Joined: Feb 2008
Posts: 170
Likes: 0
From: hopatcong NJ
this is what it does...
Or, are you saying you start it cold and then drive until it is warmed up (closed loop) and it doesn't do it at a light or stop sign (idle). Then when you cut it off warm and when re-starting it while still warm, it does it sometimes? i restarted yesterday like 7 times and it didnt do it, very weird, then day before it did it three times...maybe ill try elec lube like you said...
Or, are you saying you start it cold and then drive until it is warmed up (closed loop) and it doesn't do it at a light or stop sign (idle). Then when you cut it off warm and when re-starting it while still warm, it does it sometimes? i restarted yesterday like 7 times and it didnt do it, very weird, then day before it did it three times...maybe ill try elec lube like you said...
Burning Brakes
Joined: Apr 2006
Posts: 765
Likes: 0
From: Houston Texas
DON'T LUBE IT, use electronic spray cleaner on the MAF (insides, but be careful with the wires in there) and all the connectors (connections). The electronic cleaner does not leave any residue. 
