Hey guys new to the forum , but joined to get an answer about 2001 CHevy 1500 4.3 . It wont start when it sits for a while (3days). If ...

Hey guys new to the forum , but joined to get an answer about 2001 CHevy 1500 4.3 . It wont start when it sits for a while (3days). If it does start (after 15 min of trying) , It has a bad miss at low rpm. It runs smooth at higher rpm(3500 and up) but when it shifts gears(auto) it is like it struggles really badly too shift because of the miss, but if you drive it and get it up to temp for a while and turn it off it starts right up and no problem. It only does this when it sits for a while and cold starts. I have changed plugs and wires twice and fuel pump. I can hear the fuel pump wine when I turn it to the on position. Any tips and info will help. THX!!!

It may have a vacuum leak. The intake manifold gaskets are prone to leaking. They may seal up when the engine warms up.

That was one of my thoughts but just had to here it from someone else thanx!

fuel pump problem? thats what mine was check your spider injectors

Did you find out yet what the problem is?

sorry the forum kept giving me an error and wouldnt let me reply, but Looked for a vacuum leak and couoldnt find one , but saw where you can use carb cleaner to check the intake gasket(not sure how effective) but thought i would give it a try. I replaced the fuel pump recently and can hear it turn on so dont think that is the problem.

shot in the dark..but possiblly plugged converter? is it throwing any trouble codes?

Its throwing P0446 Evap emission control but not sure if that is what is causing it and i could very well be wrong lol just lemme know what you guys think. Thanks!

well if u can get it to run and idle for a little bit...reach under and feel near the convertor...it will be throwing noticablly more heat than the rest of the exahust if its plugged.. just saying to maybe rule that out, its hard to diagnose when u don't drive it...maybe someone else will chime in...dose it seem underpowered when ur driving it..other than the miss?

yea it is lacking power. We got some 60deg to 70 deg weather and it started right up and no prob. now that the temperature outside has dropped to the 40's and its rainy it hard to start and misses.