The Tahoe seems to have fuel pressure issue. Got a gauge and it runs 54-56 while running, jumps up to 60. After a 2 hrs it was down to 40, then 20 a few hrs later. This has happened before, hard start like not firing or getting fuel. Checked and have good spark. Once started it runs great. I put Seafoam in the last tank and it ran great from Sunday to Sunday. I use it Saturday, no issue, but did not start Sunday. I pulled the plugs and they appear to be wet. I think fuel is bleeding down into the cylinders. Yesterday I went and replaced the regulator. There is no Vaccuum line attached? Not sure why it does not have it. Anyway, back together and now it bleeds pressure as soon as the pump cuts off. What have I done? I looked for leak at fule inlet pipes and at fule line connection, none seen or smelled.Please tell me I don't have to take all apart again.
Thanks in advance.

 

OK. I have good steady pressure at the fuel inlet pipes. Guess I will be pulling the plenum to check for leak under it.

 

Not sure how many miles you have on yoru 99 but, if I were going to pull the plenum I would repalce the injectors and poppets while your there.
Make sure the fuel lines are seated well and the o-rings are in good shape not torn or cut.
Keep the forum posted...

 

Looks like I got a bad regulator from parts house. Put the old one back in and it is back to holding pressure for several hrs. I am leaning to replacing the cap and rotor to rule out ignition. The symptoms are the same as when it would not start once after I washed the motor.

 

Check the check valve after the fuel pump. The check valve is located in the fuel pump assembly (large plastic hosing that the fuel pump is located in). This is exactly the symptoms my friend was experiencing and it turned out to be this check valve. Inexpensive part but a lot of labor to replace.

 

Well, replaced the cap and rotor, put all back together. Started right up. Drove the next day, ses light came on, p0171. Lean. Did the leak test around the plenum. Found I had left the pcv hose off the intake tube. I was sure hoping intake was not leaking. Been doing fine since.
I sure do appreciate all the knowledge from this site.

Now off to replace the evo, or steering wheel speed sensor. Had to argue with the napa guy about it's existance! Turns out it is out on the floor, not behind the counter. P/n 620-2250 if it helps anyone in the future.