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mr456
08-18-2002, 04:33 PM
You said your a mechanic right? Well I will assume automobile mechanic. Any way I have a 1988 Chevy 4x4 5.7 TBI, 700-R4 tranny,light 3/4ton truck.
Anyway thing just starts runnin like shit about a week ago. Only upon hard accleration..falls on its face. Since last week I have put on: water pump,coil,plugs,plug wires,cap,rotor and it didn't do shit. It would start barely and needed to be blown out to run worth a crap(accelerator to the floor to start it too)

So I decided to change the ignition module. After this it popped right off and ran fine. So i put all my tools away and then its starts running shitty again. If you punch it at idle it is VERY responsive...but as soon as you try to put it in gear, the rpm's drop and it won't go..even if you try to feather the throttle..it just dies. Then you have to floor it to get it to start.....then its got great throttle response..then you try to move and it dies!!
I have also checked the timimg and it is right on the money. I was getting NO codes until I had to unplug the EST sensor to check the timing and now of course I am getting a code 42 which is that sensor. I cleared the codes but am still getting a 42. All I know is that I am at about my wits fukin end!!! If you got any ideas please feel free to share them with me. My personal opinion is that it is getting too much fuel for one reason or another...cause its blowing black smoke out the exhaust....anyway let meknow if you got any clues..cause I am about ready to sell it!!! Thnks...........456

PUMPINSTEIN
08-18-2002, 04:59 PM
bro check the fuel pressure . on tbi engines tap in at the fuel filter, change the fuel filter while at it. done hundreds of Gm products. weak fuel pump will usually not set any type of code. sometimes the fuel pump will start to get louder as it wears, also if it has a pulsator above fuelpump replace with screan(fuel sock).

mr456
08-18-2002, 05:18 PM
Fuel filter was changed last year. It just seems that its getting TOO MUCH fuel. I have noticed a loud sound when i click on the key. Like a pump turning on....wouldn't weak fuel pressure cause it to run lean rather than load up? I do have a small leak in my fuel line between the pump and filter..would that cause any of these problems? I sure hope its not the fuel pump..fukin in tank pieces of shit...who designed these trucks anyway?..........456

PUMPINSTEIN
08-18-2002, 05:34 PM
They suck i work in the salt belt so i get to work on all the rusted out junks. I would check fuel pressure first. they computer will do some weird things , like try to richen up the fuel mixture when it thinks its lean. but if the volume of fuel isnt there it cant . try the filter first maybe its pluged up i change mine every 15000 miles in all my cars. It idles good right ? also a common thing on those is erg valves that open too soon. you will get a stumble off idle .

PO644
08-18-2002, 06:01 PM
456 i think PUMPINSTEIN hit her right on the nose here bro the more fuel demand the more call from the pump and it sounds like its not gettin the fuel it needs try pullin the pump from the tank and check the screen around it , it might have picked up some shit from the bottom of the tank also ive heard that chevy has had this problem when the tank it made they dont clean all the shit out from the tank and then it is picked up by the pump..just my .02 good luck but im pretty sure thats your prob

mr456
08-18-2002, 06:14 PM
Thanks guys....Fuel filter has about 5000miles on it and EGR valve was replaced last year also. I only drive this truck maybe...3000-5000 miles a year..but it sure would be nice if the piece o poo ran when i needed it. I think I will check the fuel pressure and see if that isn't the culprit. If its not then I will be bugging you guys again...thanks.......456

tvman
08-18-2002, 06:29 PM
Hi, mr456. I had a 87 blazer with tbi. I would get the same problem you describe quite often. I'd change the fuel filter and good to go. Once I changed it and 6mo's later happened agin.
Did the filter agin and alls well. The gas now a days is dirty.
good luck