I'm out of ideas, guys. (Truck runs like crap no matter what I do).

[X-Cutioner]

the ground for the pump is in the connector which then runs back into the harness
if you remove the bed which forces you to remove the ground attached to the frame it will still start just fine

 

[tscherbi]

Which ground is for the pump? The one on the frame right behind the tank had corroded and broken apart awhile back, but even with it all messed up it ran fine, just had no taillights lol. And yeah, i need to get a pressure gauge on it quick.

I believe there is a ground wire comming off the pump that is grounded to the frame right by the tank. I could be wrong but its worth checking, i havent done a tbi pump in a while

 

[jdyates]

im going to throw another thought into this thread
check the injectors
my dad has an 89 with a 350tbi in it and he had the injectors start to fail in it. it started with the computer going bad causing the driver side injector to quit firing randomly, then the injectors began to leak, then a head gasket blew. We messed with that truck for over a year and during that time the injector wireon the driver side got pinch which burned up the injector driver circuit in 2 more computers that we had before we had found the bad wire. after all that the iac valve started to give us fits and would set the CEL but after driving the truck for about a month it finaly cleared up and has been running great since then.

I have literally had 3 different sets of injectors in this thing in the past month. Did the same thing with all three sets. Also rebuilt the TB and injector pod, and the FPR.

 

[5spd Z71]

along with checking the fuel pressure with a gauge, check your vacuum with a gauge when your driving around as well.

 

[Gatorboy]

Check your vacuum line going into the ring that surrounds the injectors, under the air filter on the back side. I knocked mine off when changing the distributor and caused it to go crazy. Had a real bada$$ cam sounding lope at idle, but ran like crap. Couldn't figure it out for anything, then finally I noticed it after going through almost everything else.

 

[jdyates]

I've already checked all the vacuum lines, and a second ago, i had the engine on, and it was doing its same up-down-up-down "cammed" crappy idle, but i put my ear up to the tank and heard the fuel pump humming very consistently. It didn't sound irregular in any way. If that makes any sense lol. All i can think of is the timing. Literally everything (including vacuum lines, sensors, fuel filter) has been replaced or tested. I'm gonna start playing with wiring in the rear end tomorrow. Too dark outside and I don't have any crimp connectors.

 

[iEnding]

Mine did the same thing til I changed the TPS sensor.

 

[ChrisAU]

What plugs did you put in it? I'm curious, but for your problem I really don't care what they are. Replace them. Quadruple check the gap 14 times. Make sure not to bump them when putting them in. Straight into the hole, if you bump it, check the gap another 97 times. On each plug. If that doesn't work, replace the plug wires and be RELIGIOUS about wire spacing. At no point EVER should one wire touch another one. EVER.

Do this. It may not be your problem, but I scratched my head for 7 MONTHS and my fvcking plugs were the problem. Then last fall I was befuddled for 2 months and replaced what appeared to be perfectly good AC Delco plug wires, and voila.

Delphi plug wires, and a GOOD plug. I am actually running Bosch +4s just for the reason that you don't gap them.

Do this. Deteriorating driveability is ignition related. A fuel pump gets weak, not strong and then weak and then strong again, IF all your wiring is good and clean. A too small or too large plug gap can cause fouling that continually gets worse, and a burning spark plug wire will continue to lose voltage and get worse.

Start with the small things, but do them perfectly.

 

[ChrisAU]

I've already checked all the vacuum lines, and a second ago, i had the engine on, and it was doing its same up-down-up-down "cammed" crappy idle, but i put my ear up to the tank and heard the fuel pump humming very consistently. It didn't sound irregular in any way. If that makes any sense lol. All i can think of is the timing. Literally everything (including vacuum lines, sensors, fuel filter) has been replaced or tested. I'm gonna start playing with wiring in the rear end tomorrow. Too dark outside and I don't have any crimp connectors.

Don't you DARE ever crimp and tape a wire that sends signals for sensors/computers. Solder. Heat shrink. Tape. Crimped or twisted connections are very sensitive, you don't want that.

 

[ChrisAU]

Here's the thing too: if you replace the plugs and wires, and gap and route them perfectly, and your problem still exists then you can eliminate that and you'll have the parts you took off ready for the next tune up.

I forgot to mention, use dielectric grease at ALL connections. Plug to plug wire, plug wire to dizzy cap. And replace the rotor and cap with DELPHI units.