sefiroxx

2001 4wd burb with 350k. - I was getting ready to do the reseal around 275k as everything was leaking. Son blew the engine (not monitoring oil pressure). Took the reseal dollars and installed reman engine - re built tranny at 225k. Wife broke parking pawl not using the parking brakes.

Computer uses upstream O2 sensor to make minor adjustments to the fuel trim. You need to run a scanner while driving to confirm o2 and other readings as well as fuel trim

Had similar symptoms with my 04 Sierra. Possibilities: - ignition switch module on the column is going - dead spot on the starter (This was my cause) - primary wire from battery to starter - control wire/pigtail to the stater - security

Uh oh. . . But you may be lucky 1-2 accumulator (used to smooth the shifting) may be failing (cracked, broken spring, scored walls) Tps - erratic or jumpy Servo - sticky Pressure problems First 3 can be diy, last one likely needs a tranny shop

Hanging down in front of behind the fuel tank?

Sounds like cmp/ckp sensors

Picture is a little odd. . But I believe that is where the optional oil cooler pipes would attach. There is a gasket located there to seal the plate that covers the two holes.

If it's 3/4-1" then it runs up to the fuel fill on the side of the truck, if it's 1/2 or less then it runs forward to the evap canister

The evap cannister is used to capture fumes when the system is sealed (gas cap on) and pressure needs to dissipate. When filling, the air is released through #4.

Check ground connections

There is an air vent that runs along the fuel fill pipe and allows air to escape when fuel is added. If clogged, the fuel fill could slow down as air tries to escape through the fuel.

Pull the starter and you can see the flywheel teeth. Manually turn the engine (via crankshaft bolt) and continue inspecting the teeth for missing teeth or severe damage. If none, then the starter or solenoid likely has a dead spot.

New radio then - ground connection on the interior is going bad

Do you lose sound or just the display?

Not a few pot holes and run up the curb - yep they could be toast.