markmark1121980

Had a 347 built and cant get it running right. I wont idle smooth and have to give it gas to keep it running. When I take it out and drive it, it cuts out and has a huge hesitation. When I unhook the mass air sensor it has more power and runs better while driving but the idle is worse. It has 30lb injectors and sensor. It also has a 75 mm throttle body. Trick flow heads, intake and cam kit. If you could point me in the right directoin that would be great.

tinman

I'm a carb guy but it sounds like a vacunm leak to me. What is the idle vacunm measure to?

markmark1121980

i have no idea how do you check that? Im not a mechanic at all

gt884me

Could be anything...vacuum leak..was this a mass-air conversion done recent? adjust your valves properly? might not be opening right.

mjr46

run a koer test first and check for codes

AdderMk2

make sure you didnt connect a vac line to your MAP sensor... since you likely have a MAF conversion