I have an 86 z28 camaro with an electronic quadrajet iv already replaced the fuel filter and fuel pump as well as ive dropped the tank and replaced the pickup strainer. All the fuel lines seem fine theres no leakes. ive already tried checking for vacuum leaks at the carb and it doesn't try to rev up when spraying starter fluid around the carb body. Compression test put all 8 cylinders between 119 - 122 psi. Im not sure whats wrong with it maybe the mcs or tps is bad maybe the computer??? Maybe the accelerator pump??? Bad float position???

All i know is in neutral it revs up fine it sounds awesome but as soon as I try to drive it it seams gutless and then starts to buck and bog but at times it like picks itself up and starts to take off like a rocket. But it's mostly not drivable. Like if anyone has any idea what it might be id really appreciate any info before I just start pulling apart the carb.

 

It could be time to check the M/C solenoid adjustment. That's going to require an old-school dwell meter or process multimeter with duty-cycle capability (essentially a dwell meter function). If the solenoid is not cycling rapidly under design conditions, there could be a problem with the carburetor, or could be a problem with the feedback to the ECM from the oxygen sensor.

Of course, it would make sense to check the TPS voltage at the same time, but the TPS is not all that is required to make the system function properly.

If the TPS is within reasonable limits and the M/C adjustment stops cannot be made to achieve the correct duty cycle, it may be the float level is incorrect, carb has internal leaks, passages are plugging, or some other adjustment(s) may be required. This is all assuming that the choke is operating correctly and is fully opened when engine is at temperature, the inlet fuel filter is clean, and that idle mixture adjustments cannot be made to correct the mixture control operation.

 

Might be a timing issue. Large cap HEI? Might be time to just replace the distributor.

 

Ok so today I decided to take the carb apart and I found several issues with it its slightly hilarious idk who put it together before i got it but they weren't to bright. So the driver side idle screw was completely bottomed out and the passenger side was out 6 1/2 turns lol. Also the float was set way wrong it was probably only filling the bowl about a 3rd of the way. On top of that the tps sensor didn't even have the plunger to depress it so i got a new tps and it thankfully came with one. Now the icing on the stupid cake is the secondary metering rods were put on backwards if that makes sense basically they wouldn't even sit in the proper position also the hanger was bent way up in order to get it to screw on in this wrong position if that also makes sense. So thankfully now my z28 is doin nice smoking burnouts and moving like a car should.

 

Good work. Thanks for posting the resolution to the problem(s). What you describe makes complete sense with the symptoms you reported.