sefiroxx

Does not go into D,4. . . Does the shift lever go into D,4 and the car not move, or did the shift lever not move that far?

Search for critter damage. Start with the water temp sensor and go back (temp sensor is what triggers close loop).

Same problem as every other I presume. The integration with the a pillar especially at the rocker and the tie in with the bumper.

Probe relay sockets to see if power is there. Trace backwards from there. Connect alternate ground at fan connector and trace forward. . .

Of positive, the extra fuel is being added, negative them fuel is being removed. High negative fuel trim; - MAF sensor problems - high fuel pressure - leaking fuel pressure regulator diaphragm - faulty evaporative emissions components - leaking injectors - defective O2 sensors - exhaust leaks/pinholes before the O2 sensor - coolant temp sensor problems - low compression - incorrect camshaft timing. High positive fuel corrections: - MAF and O2 sensor faults - vacuum leaks from intake gaskets/hoses - unmetered air (intake snorkel leak) - clogged or dirty fuel injectors - fuel delivery issues - exhaust restrictions Since your problems are on one side, and apparently affecting all cylinders, only components that are dedicated to one side are in consideration - the O2 sensors, (then the wire harness to the injectors)

Better scanner/code reader will provide data stream showing what the o2 sensors are sending

Computer runs on preset when warming up. Once warm the computer users input from o2 sensors etc. Get a code reader to see if anything is set or history. Get an better one to see what the o2 sensors are sending back.

Faulty ground for the dash

O2 sensor failing. Causing system on that side to run rich. Carbon buildup may be causing misfire.

Outside, driver side. Cable from the shift lever as well as wiring harness are connected. The shift lever moves a connector around and sometimes gets out of alignment

Per FSM, the dash ground points are located on the upper support rails for the dash. It's a upward facing bolt. The two dash ground pretty much split the dash and door grounds B Pillar covers the rear doors and beacon lights on pickups The ground under the driver seat covers the seats (Generally speaking)

Neutral start safety switch mounted the transmission.

Thermostat are slow adjusting - once hot, they'll stay open. Sounds more like water pump or air in the system

Passenger space for this gen has 4 ground points. 200 series are the dash area, 300 series are seating space, 400-800 and higher are doors and farther back. FSM shows two dash points. Either end, bolt faces up, on rail, near the A pillar. Two body points. One under the driver seat for use the power seat circuit. The other is on the driver B pillar some 6-8 inches up (older GM's had this hidden under the door/floor trim)

Ground is located outside on the rail. The module is located inside frame, driver side, ground point is farther back and on the body mount point (along with a couple of other ground wires)