Fuel pressure question

[ruckusz28]

I'm running a new edelbrock 600 carb, and mechanical fuel pump on my car. My fuel pressure gauge bounces between 3 and 7 lb of pressure. Is this acceptable or should my fuel pressure be constant?

The reason I ask is because once my car warms up, it runs like crap in gear at low rpm and buck back and forth. Once this starts happening, my idle goes to crap and a times the car will stall.

Heres the back story, the car had a 750 Holley on it at the beginning of the season. This problem began and I replaced the carb thinking it was too much. The problem continued until I replaced my fuel pump with a carter my buddy had used in the past. The pump was not new. This seemed to solve the issue for about 3 months.

Now the issue is back and I'm at a loss. New plugs, wires, fuel filter, fresh gas.

Any ideas?

[dawdaw]

i'm don't know much about carbs but fwiw on my neighbors 442, the 10 seconds that it's going down the track, there is 0 fluctuation in fuel pressure. does the car fall flat on it's face when you go wot, or a few seconds into wot? what jets are in the front and rear? what air bleeds are in it? also does it have a wideband? how does the car run midrange and wot?

[ruckusz28]

I'm not a carb expert but its whichever original jets / bleeds came on a 1406 edelbrock. The car runs great at mid and wide throttle. There is no wideband on the car.

I opened up the carb a bit and it seems to have resolved the issue. Once I did that, the fuel pressure stabilized at about 6 lb. Made it to Woodward and back. About a 50 mile round trip!

[Sic96]

Glad you figured it out, but yeah, it should be pretty consistent. 6-7lbs. is about right for a mild setup. My uncles 10sec. stang runs about a constant 8 psi. Whole different ball game than FI, that's for sure. I idle at 43psi lol.