i have a 1972 chevy blazer with a 350 V8. its been sitting a while, and when i try to drive it after it sits for an extended amount of time, it misses when i accelerate and dies for a second when i stay on the gas. i assume the valve timing is off or something? any help would be appreciated. and yes i know this is a ford forum but i figured i could shoot for some help anyway. thanks!

 

what makes you think the valve timing is off? did you redo the timing chain or something? does it back fire? out of the carb? that would make me suspect valve timing.. It could be that the ignition timing is to far advanced. Could be your carb is in need of an over haul.. could be it needs a new fuel filter. Have ya done any maintenance?

 

Accelerator pump not working will make it hesitate when you step on the gas.

If timing was off it would run crappy all the time, not just cold.

 

in case you didnt figure it out i dont know too much specifics about engines. im a motocross guy and only know 2stroke engines. but i do believe it was the ignition timing, because my dad has fixed it before with a timing light i think its called? but then it sat for another 6 or 8 weeks and its having the same problems. there is no backfiring, and the only engine adjustments we have made is the timing i just talked about. there are no other problems, it will just accelerate and at a certain point either die for a second or just put put put along.

 

You've gotten the correct response. The carb accelerator pump is bad. When they first start going bad you can semi cure the issue by advancing the timing which makes the engine react like you have richened the fuel charge which makes up for the missing amount of gas that the pump would have injected into the manifold. Fix the carb and yer problems will be over.

 

Does it have points or electronic ignition? If it has points, you have to set the point dwell, then reset the ignition timing.

 

thanks for all the help. i have also gotten a few suggestions that it might be the distributor hold down is loose. my dad is the mechanic and knows all this and im sure we will get it fixed or at least pinpoint the problem.

 

If he's thinking the hold down is loose, it may be worn distributor shaft bearings/bushings. I had that in an old BMW and it ran like total crap.