2003 Yukon XL

Couple4Fun48036 · October 4, 2018

Here's one for you veterans...

I replaced the block and had the heads reworked for my 2003 Yukon. 5.3l. L59 Block, Vin z. Got it all back together and it started up. After it idled for a bit it stalled. I figured maybe the gas had evaporated. Brought home a 5 gal can. Started up. Did the same thing. Put a gauge on the fuel lines, pressure seemed funky. About 45psi. Replaced the pump. I went right through the floor. Started it up, worked the air out and it was much more responsive. However, within a couple mins, it stalled again. Does the erratic stall, rev, stall rev until it dies out. Can jump on it and it comes right to life until it gets warm and then it starts to do it's slow death routine.

New pump, new filter. The only thing that's not hooked up yet are the O2 sensors from the y pipe. I haven't tied the exhaust back in yet, just headers on it ATM. No leakage from the fuel pressure regulator. Replaced that line as well. And yes, the map sensor is good as well. The throttle body didn't seem to have any issues and sat on my bench for probably 3 months while I slowly got it all back together. New gasket on that as well. I did notice that the replacement block's OSU needs replacement but that seem to factor into this at all. Just wishing I would have done it before I dropped it back in. Lol.

I'm about to cut a tree down and hope it falls on the damn thing. Help!

Thanks in advance...

Edited October 4, 2018 by Couple4Fun48036