So I have been trying everything to fix my truck. It's a 94 silverado with the TBI 5.7. I have done the complete tuneup, pligs, wires, cap rotor, coil. I replaced the fuel pump twice. Fuel filter. Replaced the ECT sensor. Cut off the exhaust. Checked the TPS and air sensor. Replaced the intake gasket, mostly because it's been smoking for a while. Checked the timing. My truck will run great and then it starts to act like it's timing is being retarded. I found that if I turn the ignition off, and then turn the key back on and let the fuel pump run, it has power again, but not for long. Any help would be great. Thanks in advance.

 

Also checked the EGR. Could this be a distributor issue? I had to pry the rotor off of the dist. shaft when I replaced it. There are no codes stored. The fuel pump runs for about 7 second when the ignition is turned on

 

I wonder if your set up has a fuel pressure regulator. When you start to lose power do you see any colored smoke shooting out the exhaust?

 

It always smokes as it needs valve stem seals, but I'll have to watch it more carefully. Is there any way to test the regulator, or do you just replace it? Thanks for the help.

 

Well the only way is to test the whole fuel set up. If you could find someone with a good scanner and find out if it is running lean, ignition timing is jumping, maybe a misfire, all the info you would need to narrow it down. Thats what I had to do with mine on my 2001. When I would romp on it, it felt strong till mid rpm's and then it felt like fuel was being cut off. Finally I figured it out it was one of my coils was intermitently bad.

 

Okay, so I have now also replaced the TBI unit with a known good one. Still no good. I put the timing light on it when it was acting up. When it starts to act like it is choking out, it is not firing on the #1 plug. Would this mean that it is most likely fire and not fuel? If it's fire what would be the most likely problem? I was starting to think it must be the distributor as I have replaced the coil, cap, rotor, plugs and wires. If not the distributor, then what? Thanks again.

 

So today I tried a couple of different things. I started the truck and let it warm up. Then I sprayed around the intake manifold to see if there might be a leak. No change in the motors sound. I then sprayed either in the TBI while operating the throttle. It idled up and held fine, as long as I sprayed the either. So I'm back to fuel, not spark. But what could be causing this? Any one that my be able to help, please do. I'm willing to try about anything.

 

i am haveing the same problem with my truck i jsut baught
it has spark plenty of it starts every time and then frives for about 20 miles then bogs down hard almost dies i am leaning towards a pressure problem as i have yet to replace the tbi gasket
i would check that also
but anyway if you fixed your problem would you car to share
and

 

I ended up rebuilding the TBI. It didn't fix my issue. I then pulled the fuel pump and found that the screen that came with the pump I put in was smaller then it was supposed to be. It also had a bunch of crap in it. I had changed the fuel tank and didn't clean it out very good apparently. I replaced both fuel filters and siphoned out as much fuel as possible. It runs like a champ now. Don't know if that will help you.

 

well i am heading down the same road you went with your as i am going to do a tune up cap rotar plugs wires oil change and also ne tbi gasket
i already put a new inline fuel filter on the truck today and the old one had alot of rust that just droped out like goo
i have added a fuel system cleaner to fix that problem
but after i replaced the fuel filter it did the same darn thing droped below 1000 spit and sputtered died out
i am starting to think that there is a vaccum leak somewhere as i sprayed wd40 on the vacum lines and pulled the throttle and it sputterd after it sucked in wd40
also the fuel presure in my truck is correct
whats really got me upset beyond belife is the guy i baught it from 3 days ago told me it had just went to the shop but then he couldnt provide reciepts and proof and also he told my frend that went with me while i was under the truck lookin at the frame that it had sat fro 2 weeks
so again if you figure yours out let me no so i can save me some money and hassel thanks