I'll try to keep this quick...

My formula has a wicked buck in the lower gears. In 1st its almost violent, in the upper gears it feels more like a repetitive stumble. Almost always occurs when holding constant lower RPM's, hard acceleration is fine. Another example, when you let off the gas in 1st, the front end drops right down like you hit the brakes. Terrible mileage too.

Relevant info:
-17-18 inches of vacuum at idle
-34 psi fuel pressure at idle w/ vac line connected, monitored while driving and the pressure never did anything erratic, so I've ruled out fuel pump
-new design III 19# injectors
-ignition timing properly set
-newer plugs, wires, entire distributor w/ module, ignition coil ohms out fine.
-newer O2 sensor, CTS, TPS voltage is fine
-NO CODES

This has been driving me crazy for 3 years. Now I think I might have a blown head gasket, and this probably helped that issue along. I'm about to take it to a mechanic, if I cannot figure this out soon. All I can think of is MAP, but without a code? If you have any idea at all, please help me out.

 

Why aren't you posting this over in the TPI sub-forum? stock 305s generally never have any issues with head gaskets. A bad intake gasket is infinitely more likely.

 

Thanks for the response,

I wasn't sure which forum to post it in, I don't know if it is a TPI specific problem. I certainly hope it isn't a head gasket! I'm still trying to determine what is going on with that, but I figured a constant knock/miss/buck would really stress a head gasket?

Took it for a lengthy drive last night, feels like half the cylinders just drop off at times. I'm at a loss for what to do next.

 

I have the exact same problem with my carbed 350. I've checked for vacuum leaks in the intake/carb gaskets with starting fluid, replaced plugs, wires, cap, rotor, even tried a different carb but still have the same issue