Runs Rough Under Load

[97Yukon4dr]

Spec is + or - 2 degrees at ~1100 rpm, not "somewhere between -20 and 60".

my bad lol I mixed up the hold-down bolt for the actual distributor with the cap.

 

[Schurkey]

It may have been incorrect because I was idling at around 750 when I checked it.

Yep, idle needs to be higher.

i don't understand how loosening that little screw can help change the cam retard...

WHAT "little screw"?

the distributor cap can only bolt down one way so how is it possible to change the degrees. wouldn't it just causes a bad connection temporarily between the cap and rotor

The distributor cap has no effect in adjusting cam offset. Other way around--cam offset changes the relationship between rotor and plug wire terminals.

 

[Essayons]

my bad lol I mixed up the hold-down bolt for the actual distributor with the cap.

Refer to the instructions I posted earlier. I’ve seen worse than -11 with no real problems but you need to check it around 1100 rpm.

 

[97Yukon4dr]

Refer to the instructions I posted earlier. I’ve seen worse than -11 with no real problems but you need to check it around 1100 rpm.

I fixed it today, bottomed it out fully counterclockwise and got it exactly to zero when revved up there was no change. it seems to idle better, shift better, and accelerate better... however it still doesn't like hills and continues to have the same problem

 

[Essayons]

I fixed it today, bottomed it out fully counterclockwise and got it exactly to zero when revved up there was no change. it seems to idle better, shift better, and accelerate better... however it still doesn't like hills and continues to have the same problem

Does it have AC Delco rotor, cap and wires? Specifically wires.

 

[97Yukon4dr]

Does it have AC Delco rotor, cap and wires? Specifically wires.

I don't believe they are ACDelco they were just ones from my shop. I know ACDelco are good replacement parts for these older gm's. I believe the old wires were ac Delco, however, it had the issue before all the brand new parts.

 

[honkon]

I think you're on the right track now that cam retard is set. That can cause funky problems. What do you mean the scanner said it was running rich? You said it wouldn't set or store codes?
But still runs rough when you push the truck hard? Does it run worse at high or low rpm?
You have to replicate this while you have a scanner hooked up, ideally with someone paying attention to it. Record the data while the truck is running rough. Fuel trims, MAF, RPM, o2 sensors, misfire counters, WHILE this is happening. Many things can cause this. Start with what u know.

 

[97Yukon4dr]

I think you're on the right track now that cam retard is set. That can cause funky problems. What do you mean the scanner said it was running rich? You said it wouldn't set or store codes?
But still runs rough when you push the truck hard? Does it run worse at high or low rpm?
You have to replicate this while you have a scanner hooked up, ideally with someone paying attention to it. Record the data while the truck is running rough. Fuel trims, MAF, RPM, o2 sensors, misfire counters, WHILE this is happening. Many things can cause this. Start with what u know.

The scanner wasnt reading a code for the rich, it was just in live data (specs from the vehicle whilst it was running).
Yes, it still runs rough, once it starts its the worst at high rpm... i have to let off the throttle for a while for it to go away.
And i cant take the scanner from the shop, and i assume cheap ones dont read live data

 

[Schurkey]

it still runs rough, once it starts its the worst at high rpm... i have to let off the throttle for a while for it to go away.

What is the fuel pressure under load?

"Load" can be simulated with most fuel pressure testers by pushing the button to bleed fuel out the little "vent" hose. Ideally, you'd pull the vacuum hose off the regulator and plug the vacuum leak.

How old is the fuel filter?

What is the spec for fuel pressure on your year/model?

 

[97Yukon4dr]

What is the fuel pressure under load?

"Load" can be simulated with most fuel pressure testers by pushing the button to bleed fuel out the little "vent" hose. Ideally, you'd pull the vacuum hose off the regulator and plug the vacuum leak.

How old is the fuel filter?

What is the spec for fuel pressure on your year/model?

I had put the fuel pressure somewhere in this thread and it was within spec, the fuel filter is new. I do believe this issue could be driveline related it only really happens when the tranny doesn't shift propperly