Shealverahdo

Against my instincts I took my truck up the road for a basic service and when I picked it up it has trouble starting up, will fire up then stumble and die like its starving for fuel, gotta turn the key on for a few seconds after that then it'll fire up and limp to life. It has a horrible loss of power and giving it any more than 20% throttle it acts like it wants to stall out, if I floor it and downshift it gets all loud and angry like it's got ***** but it barely moves and if I let it shift at WOT it backfires through the exhaust. It doesn't throw any codes which is annoying, I can't find a vacuum leak anywhere. The jackass at the place said "oh well I mean I don't know how it ran before you brought it in so there's not much we can do" obviously this place was full of idiots, I thought what's the worst that can happen? Omg so much apparently.
I have replaced a lot of little stuff just kind of trying to treat the symptom but I can't seam to figure out what the problem is, anyone see this issue and fix it before? 1999 Silverado 1500 Z71 5.3 roughly 170k

oldchevy

Find out what the shop did for their basic service. And start checking those areas. This could lead you you to the problem.

Rednucleus

Please list what services the shop performed. I assume was running fine before the service visit. I would start by checking all the plug wires

Shealverahdo

They supposedly just changed the oil and air filter, he said he didn't even do his full inspection cause they were busy, claims there's no way it could have been them, real winners there. It doesn't act like plugs or wires tho, I mean I can go ahead and throw some more money at it but I have changed plenty so far, egr valve, evap purge solenoid and bent valve, buddy tested fuel pump and it's got good pressure he says, I can't actually remember everything I've changed I'll have to look through some invoices cause it's been a couple months, most recent thing I changed was TPS. Plugs and wires would surely cause a miss

Rednucleus

I was thinking more in lines of plug wires are not in proper order based on your description; never hurts to check. Again, was it 100% normal before being serviced, and did it do this driving away from their store?

Shealverahdo

Hmm in a different order huh? I'll check that out but yeah it ran perfectly fine before I took it in and when I went to turn it on as I was leaving it kind of stumbled and kicked on, only because it was warmed up, if I start it cold it'll fire right up then just kind of fall on its face and then I can try it again and it'll fumble to life and idle normal, when I try to put it under load like simple driving is when it starts to mess up. Got it started and drove it around the block and took it back and the guy looked at it and said man I just can't figure out what I would've done to it and honestly I don't know how it ran before you brought it in here. Such a cop out, the truck ran like a bat out of hell those generation 5.3's are beasts