[crossflag]

92 LT1, The only code that comes up is #28 and that is the AC clutch/relay code which I think is a code stored from last year that i repaired. The Problem... The car will run fine then starts missing, (mostly when coasting or coming to a stop) When stopped it will surge. Sometimes it will just shut off but will start back up easy. Even when running rough it will accelarate well. The car runs very well most of the time but will act like my wife when it want to throws a fit. Injector(s) going bad?

 

[toobroketoretire]

92 LT1, The only code that comes up is #28 and that is the AC clutch/relay code which I think is a code stored from last year that i repaired. The Problem... The car will run fine then starts missing, (mostly when coasting or coming to a stop) When stopped it will surge. Sometimes it will just shut off but will start back up easy. Even when running rough it will accelerate well. The car runs very well most of the time but will act like my wife when it want to throws a fit. Injector(s) going bad?

I would start with the basics like changing the fuel filter and replacing the O2 sensor if they have more than 25,000 miles on them. Then it wouldn't hurt to do a fuel pressure check at idle and also when driving down the road. You can duct tape a pressure gauge to your windshield then observe the pressure under all running conditions; especially at full throttle as the pressure should stay the same if the fuel system is up to snuff................

 

[crossflag]

I would start with the basics like changing the fuel filter and replacing the O2 sensor if they have more than 25,000 miles on them. Then it wouldn't hurt to do a fuel pressure check at idle and also when driving down the road. You can duct tape a pressure gauge to your windshield then observe the pressure under all running conditions; especially at full throttle as the pressure should stay the same if the fuel system is up to snuff................

The fuel filter was replaced three years ago, 8.000 miles. I have a fuel presure gauge mounted under the hood and allways reads the same. reving the engine (no load) it will increase from 35 to 39. New plugs last fall, wires and opti are three years old. The car runs perfect most of the time but then at times will start bucking, surging and may just shut off but will start back up easy. Then it will clear out and run great again. I dont know how old the o2 sensors are but no codes are showing for them. Altough These symtoms are the same for a opti going bad it dosnt last that long then runs great again??? When the optis go bad the stay bad!

 

[toobroketoretire]

The fuel filter was replaced three years ago, 8.000 miles. I have a fuel presure gauge mounted under the hood and allways reads the same. reving the engine (no load) it will increase from 35 to 39. New plugs last fall, wires and opti are three years old. The car runs perfect most of the time but then at times will start bucking, surging and may just shut off but will start back up easy. Then it will clear out and run great again. I dont know how old the o2 sensors are but no codes are showing for them. Altough These symtoms are the same for a opti going bad it dosnt last that long then runs great again??? When the optis go bad the stay bad!

I would still tape a pressure gauge to your windshield then observe the fuel pressure under driving conditions because that's the only way you would ever know if the pressure is staying high enough. Just blipping the throttle when it's sitting still doesn't tell you anything because a full throttle blast will consume about 100 times more fuel. A typical 350" engine will consume about 40 to 42 gallons per hour at wide open throttle and there's no way you can ever duplicate that amount by blipping the throttle. Trust me as I've been twisting wrenches professionally for over 45 years.

The only way you'll ever know if your fuel system is up to snuff is by taping a pressure gauge to your windshield then take it out and do a 3rd gear blast up to about 100 mph. The pressure should stay around 38-39 psi all the way up. If it starts falling off then you have a failing pump or a plugged fuel filter. Also a failing fuel pump relay will also cause "bucking" so if your relay has many years use on it I'd suggest replacing it based on mileage alone. As the relay has mechanical points in it those points WILL get carboned up and quit making continuous contact. The relays are only about $15 and available at any auto parts store.

 

[vetteoz]

a failing fuel pump relay will also cause "bucking" so if your relay has many years use on it I'd suggest replacing it based on mileage alone. As the relay has mechanical points in it those points WILL get carboned up and quit making continuous contact.

All C4's have a separate switch operated by oil pressure that powers the fuel pump direct from the battery ,independent of the pump relay anytime the engine is is over 4 psi OP

 

[crossflag]

Drove the car 80 miles last saturday without a glitch, then On sunday a short trip into town. On the way back at a red light it started surging. I put it in netural and the tach went to 2500. Light went green, put it back in gear and it was fine again. would a bad fuel pump or regulator make it surge?