My buddy has a 99 24v with 350k on it and is some what stock has 4" exhaust and it has a power puck on it and he seems to think that there was a programer in it but the original owner did not have the programmer so the program is still in the ecm. Anyway last night he was messing around getting on it and the truck died taking off from a stop. He fired it back up but the truck is missing badly. I did put a fuel test gauge on it and it is at 5psi I know that this is low but think that it has been this low for awhile now. When it idles it has a definate miss and lopes real bad and there is no throttle response. After it runs for a while it will pick up and smooth out a bit and still has a miss but not a bad and does have some throttle response then. Any ideas on what this could be or what to look for or what to do. I am thinking and injector went out but idk for sure. Any help would be greatly appreciated Thanks!!

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Update I just pulled the power puck off and it idles smooth just wont accelerate very well it is very eratic and wont rev up very well maybe up to 1200 rpm or so.

 

any codes?

 

The cel is on but I cant get it to read out any codes by cycling the key off and on 3 times its now idleing smooth just rough once you try to accel and wont go over 1k rpm's

 

There are some codes the key trick will not work on.You need to get,rent a OBD 2 scanner.

What kind of lift pump?5psi

 

CEL key trick doesn't work in 99.

 

is it smoken heavy

 

No no smoke ocassionally a bit of white smoke but not to much at all. I have another lift pump that is better than the one that is on it that i am going to try and see if that helps because when you try to accelerate the fuel psi drops way off to almost 0 psi.

 

well he needs to get a fuel pressure gauge. then scan for codes. check the fuel filter and make sure it isnt gunked up. 5 psi is not enough pressure. maybe at idle it will run but definately not when accelerating. check the lift pump and the vp as well just for piece of mind.

 

Sorry to say - its time for a new pump (and a fp guage)...

 

Yea I'm hoping that the pump will help it i am trying to get a scanner so i can scan it and see what it has for codes. I also have been preparing him for a vp as well and also an air dog or fass set up along with gauges so we will see what happens. Is there a way to test the VP and see if that is the problem?

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Well I was able to get ahold of a scanner and the codes of interest that I got was P01688, P01689, P0251, P01689. I cleared the codes and started the truck and the only ones that come back are P0251, and P0252. Do these definatly mean time for a new VP or is there something else that could be wrong? My buddy doesnt have any $$ for a pump if we can figure something else out that it could be just trying to help him out as cheaply as possible. And thanks guys for all of your imput so far.