sefiroxx

3rd geer operates with the solenoids off (limp home mode) When shifting into 3rd, the solenoids turn off, valve return springs push valves into default locations including a fluid routing that pushes a 2-3 passive valve into a position that engages the 3-4 clutches. If you are not having problems in 4th, then your clutches might be ok. I'd bet on valve/body problems. Start with a full fluid change, and see if that flushes out something that be causing a sticky valve. Check your fluid/pan for clutch material. If the flush doesn't help, probably time to drop the valve body for a rebuild.

Someone cut the switch out. Std gm setup has the switch controlling brake lights (1 pair of wires , normally open, routed thru relay) and cruise control (other pair of wires). The cruise circuit might be normally open or closed depending I the engineers creativity that day of design.

Tada. . . It'll need a relearn. Let it idle for a minute. Shift through the gears. Turn on the ac. Turn off. Restart and take it for a drive.

Probably fuel pump/pressure. Before the 1st start, try turning key on for a few seconds, off, then start. If it improves, then fuel pump/filter.

When it started, did you keep holding the pedal down? BTW, the ISC only controls the air gap. If the fuel pressure problem is still there, then the isc test will create a more lean condition.

You can verify the isc problem on startup by giving a teeny bit of pressure on the pedal. That will manually open the throttle like the isc is supposed to do.

Check engine ground cables as well. Also, check the wires etc in the main fuse box. Try wiggling fuses Etc and shaking the wire harnesses underneath.

4WD? Have you jacked the truck up and watched and listened? Any codes?

Typo?

Pick n pull time

- CRC MAF cleaner - if you smell fuel at the vacuum connector, then the diaphragm in the regulator is leaking. Recommend a new one. Also, have your fuel pressure tested. You can rent a pressure tester at the local parts store. (On or 3rd fuel pump since purchasing our 01 new. - clean your throttle body and butterfly. - your ISC motor may be going. It controls the opening of the butterfly to allow for higher idle under cold start.

Ditto, 04 Sierra, the dimmer switch turns on dome and door lights.

My 04 Sierra 4.8 nearly hits 60 on a cold start and settles to 50 on Hwy and 40+ on idle. 01 Burn 5.3 with rebuilt engine and upgraded pump starts at 60+ and idles at 50-. Before the rebuild, it was 30-40.

I'll have to pull out the fsm. . . . . But for a quick guess - if the door lights are on, then the circuit for a door switch is showing open door - relay is stuck on - door switch wiring is shorting out.

Does a regular cheap scanner work? If not, then check fuses and grounds. If yes, then call the tuner mfg.