Idles fine no power under load
I have a 88 k5 350 tbi that was converted over to a standard trans believe np465 4x4. We just had the motor rebuilt and got it back in truck and hot it to idle fine and revs fine in neutral but as soon as you put it in gear it want do die and has no power. In first you can over rev it and get it to move but you have to keep push in and releasing clutch if you shift it in to 2nd it just has a constant jolting like as if you released the clutch to fast but it doesn't go away at any time. And if you put it in 3rd it hardly gives enough power to move. Any thoughts their I'd no check engine light. New cap rotor plugs wires icm coolest sensor. No cats so can't be clogged. Checked all vac for leaks. And spayed carb cleaner looking for leaks. Haven't been able to get fuel pressure fitting for tbi yet but has good cone spray out if injectors. New fuel filter. Any suggestions I have been messing with timing so I don't think that's it. I even double check to make sure rods were not to tight. Clutch has pressure. Trans was swapped before rebuild engine and worked fine then thanks for any imput. Oh yea also used know working tps and map and iac sensor

 

Sounds like a fuel related problem, check fuel pressure.

 

I had the same problem. For me, it was the little hose between the fuel pump and sending unit inside the fuel tank. It had developed a crack, and so I didn't have good fuel pressure. Changing that little hose fixed it all.

 

You say that you have been *messing* with the timing. Do you have a timing light?
Did you set it to 0* with the brown connector unpulgged? If not do that to rule out timing.

If there is a good spray from the injectors I would not suspect the fuel pressure.

 

I was gonna suggest the timing too, almost sounds like the problem I had on my chevelle....timing was 180* out. Ran and idled great in P and N but no power in gear.

 

I was gonna suggest the timing too, almost sounds like the problem I had on my chevelle....timing was 180* out. Ran and idled great in P and N but no power in gear.

 

You had a engine run and idle great with the distributor 180* off?

 

Yep, ran and idled fine, rev'd normal....no power in gear. Wondered why my hotrod wouldn't burn off the tires after a new HEI distributor and coil.