Thanks for all you quick resposes and all the good information. Next question could it be the fuel return line being plugged. I ask this because i read that it could cause the injector pump not to work. I also heard a loud hiss when i took off the fuel cap when it was having problems last night.

 

Loud hiss isnt good try blowing compressed air into the tank and try running truck with the fuel cap loose

 

what does that usally mean. Could it be the return blocked.

 

That means the tank isnt breathing I have never heard of a clogged return line but that doesnt mean that isnt the case though

 

Ok I'll have to check that as well. Thank you for your help and I'll post more after i do some checking. Thanks for all the information.

 

Some miss information posted here.

The LP on OBD1 is powered during cranking by the LP relay,once the engine is running and the key is released from the start position,oil pressure builds and the OPS takes over the LP power duties.

OPS are common failure points with OBD1 and can fail only on the LP power circuit and work perfectly fine on the gauge circuit.

OPS/LP test is performed by opening the water in fuel drain valve while the engine is running-if it contines to run with the valve open the LP is working-if it stalls the LP is not working or not working well enough.Often from a bad OPS,a clogged fuel sock in the tank or a plugged vent in the fuel cap(large hiss when cap is removed).

The OPS was underbuilt by GM for the power flow required and extremely light duty from the aftermarket suppliers,the LP draws approx 15 amps and the switches were built by GM for 10 amps-aftermarket 2 amps.

It would be wise to replace a questionable OPS with AC Delco only and add the OPS relay mod(google it).

DTC 35 - Injection Pulse Width Error (Time Short)-sometimes associated with the PMD,or can be helped with increased fuel lubricity,marine 0 ash 2 cycle oil in the fuel at a ratio of 1:200 is needed or commercially available fuel treatments.

DTC 84 - Accelerator Pedal Position Circuit Fault
DTC 99 - Accelerator Pedal Position 2 (5 Volt Reference Fault)
Both are serious driveability codes dealing with the throttle peddle resistor circuits.

Stalling can be PMD related also and getting a new PMD on a heatsink outside the engine bay with a PMD resistor installed is the best chance it can have for a long life-but they all fail eventually.Carry a spare PMD/heatsink/resistor combo for emergencies.

 

well after reading about pouring water over the pmd to see if it starts I decided to try it and sure enough it started. I shut it off and again it wouldn't start poured more water over it and it started again. I guess i know what to change. Thanks for all the information.