2007-07-22 07:33:45 · 8 answers · asked by Paul b 3 in Cars & Transportation ➔ Car Makes ➔ Pontiac
I should have added I have a rebuilt Carb from autozone on engine as well as ACCELL Plugs and wires and timing was just set by a pontiac mechanic
2007-07-22 10:04:24 · update #1
maybe not getting enough air. My father-in-law has a 400 in his '77 Grand Prix with a 750 Q-jet and his falls flat on it's face under hard acceleration until he get's up to speed. The other day he tried driving without the aircleaner on and he said it ran a lot better. If you have the factory style snorkel air cleaner try an open element air cleaner system. I would try this method first before spending money to rebuild your carb...
2007-07-22 07:48:06 · answer #1 · answered by Camaro355Z/28 3 · 0⤊ 0⤋
Assuming the timing, coil, ignition wires, plugs , cap and rotor are ok---it might be an internal carb problem with the power valve---which is vacuum operated--- or the accelerator pump is worn. Just have the carb rebuilt by a good shop or buy a rebuilt or new one but make sure it's for your year, make and model as there are lots of tuning and adjustment differences on carbs from one year. make and model to the next.
2007-07-22 15:23:07 · answer #2 · answered by paul h 7 · 0⤊ 0⤋
Just a shot in the dark here as most of these people seem to be on the right track with you.
Make sure the choke on the carb is not closing for any reason, Try to wire open the choke then try it again.
The way it sounds it has to be the carb, or a over or under pressure fuel supply and or fuel slosh.
Go with a #1407 EDLBROCK and you will be very happy, as anything else your going to have to tune every day booo Holley!
Good luck
2007-07-23 08:06:15 · answer #3 · answered by RAMairGTO72 3 · 0⤊ 0⤋
The Discount Store rebuilt Q-jet could be pretty badly calibrated or even internally damaged. They're not known for good operation. So I would look at that first. It is helpful to know whether the problem lies with the primary or secondary side of the carb. Drive with the secondaries closed, and see if it's okay or not.
If it is the secondaries only, then they are pretty easy to adjust.
2007-07-23 00:36:01 · answer #4 · answered by Firebird 7 · 0⤊ 0⤋
You could try a couple of these. It is running too lean, adjust the air/fuel mixture. Advance the timing regardless of who may have timed to stock after it being modified. Put higher octane fuel in it. Or the motor is tired and needs a rebuild.
2007-07-24 21:15:31 · answer #5 · answered by clowdy4 4 · 0⤊ 0⤋
You need to rebuild your carb, sounds like your accelerator pump is bad. this shoots fuel into the carb under acceleration so you dont feel a stumble or as we refer to it a "bog"
2007-07-22 14:46:23 · answer #6 · answered by Christian 7 · 0⤊ 0⤋
Sound like it is running to lean or rich at the low end. Possible air or fuel restriction
2007-07-22 14:49:12 · answer #7 · answered by rxl95 1 · 0⤊ 0⤋
try readjusting your idle mixture screws.
2007-07-23 17:14:58 · answer #8 · answered by miiiikeee 5 · 0⤊ 1⤋