I've dont all I can think of with my 305 TBI. I've changed the fuel pump, fuel filter, EGR valve, IAC, pickup coil, spark plugs, distributor cap and rotor, ignition coil, even took it back to GM to have it diagnosed, but nothing seems to help. My engines bogs intermittently. It bogs when first start it up, or when your driving steady on the highway. WHen it bogs, the tact jumps downwards like the engine is turning off. WHen it bogs, I step of the gas pedal to rev but car continues to bog. The main problem is that its intermittently. Either its a short or a fuel problem. Any ideas guys. If I cant find the problem...Im planning of going carburator and swapping in a 350 ZZ4 crate motor. Cheaper than buying a new car i guess. P.S. the engine has 86,000 mile on it.

 

air filter, injecters good?, cat clogged? have you scanned it for codes? i'd guess gm service did. no codes you can bet it's not related to the ecm controls. checked fuel preasure?

 

I don't know if this can create the symptoms you have, but could it be the engine ground straps being corroded or partly broken?

 

If that is an option...what are you waiting for????

 

Thanks guys.....I know the fuel pressure is good, fuel pump was just replaced. I'll check the ground wires and the cat. The cat is an after market Dynomax. If all fails, seem like a swap is in the works.