part-throttle miss?

[eric88gt]

What could cause a miss/bucking at part throttle? It seems to clear out and run pretty good once you get over 1/2 throttle, but i can't even try to maintain a steady speed or the thing bucks and misses like crazy. I've already changed the TPS and MAP sensor, neither of which seemed to change it at all. Any help would be appreciated!

 

[91GTConv]

Well it could be a lot of things. I had the same exact problem and the only thing that eventually worked was to plug my open breather elements in my valve covers. I learned this was not good while running a working pcv (creates a vacuum leak). I still have some minor bucking, but that is likely due to my fairly large cam.

If this is not your case you could always check for vacuum leaks elsewhere which cause similar symptoms.

Make sure your plugs, wires, cap, & rotor are good. Could be ect or act sensors giving false readings. Could also be maf, which I'm not sure you have.

 

[eric88gt]

Cap, wires, plugs, and rotor are all new, forgot about them. I'm pretty sure it's vacuum realted actually, i'm gonna go change intake gaskets and see if it helps, cause it certainly isn't gonna make it run any worse. I've got the stuff to switch to mass-air, i just haven't gotten around to it.