big stinky

What causes missing under load while cold? I shouldnt say cold, but after it has sit for at least an hour... Usually only happens in 1 or 2 gears when i put the fuel to it, shudders, sounds weird with a bit of blue smoke, then after that its fine, pushes black smoke.
Thanks

SmokemS

could be your lift pump maybe?

Alwaysworking

were you parked at any angle?

mine would run how i think you mean after being parked on a side hill or nose down.

torquefan

Often they would act like that with stock timing. Once the timing was advanced to 10 degrees, it would clean up a lot of that problem. Also good advice above. Fuel starvation or aeration could also be causes.

big stinky

In answers to your questions...
Smokems
Lift pump is original i believe. Just didnt want to throw money at it without it needing it. 306000 kms on it.

Alwaysworking
Happens all the time, I dont usually park it on an angle. It seems to run fine until i give er half throttle or so, then she craps out for a min.

Torquefan
Timing is at 3/16s ish advanced from the stock mark. Any more and it gets noisy on cold startup. Had it advanced more, but backed it off.

Could this be bad injectors too? As in pop pressures getting low and a bad spray pattern, or do you folks think its delivery issues?

flashgordon

Mine us to chug and have a hard time excelerating form dead stop cold,(in cold weather.) if i tryed to mash it.
after the 1/16 timing bump, the problem has gone!

Flash.

torquefan

I would think it could be either. Getting the injectors tested may be a good idea, after you rule out any supply problems.

Montana2x2

Mine did it to a small extent when my KSB sensor crapped out which seconds what Torquefan says about timing. A diaphram lift pump will not cost you much more than installing a fuel pressure gauge which is nice to have when you run into problems like this, besides a pyro I consider this one of the most important add on gauges. Good luck.

powerrammaster

I have the same issue, worse than ever. I am wondering if it is air from a delivery problem. It does it when the engine has cooled back down to outside temps. Smokes blueish white like a mosquito fogger until I get the rpms up. Seems to do it after like 6-8 hrs sitting. My idea was KSB, though it is not cold outside. Will that still have a bearing on this? I don't want to bump the timing yet, I haven't done anything recently to make this happen, so I feel I should look to correct an issue. Sorry, didn't mean to hijack, we have exactly the same issue at the same time. BTW the problem is on the 92 i/c truck.