Flip66

iTrader: (1)

I have a 350 with a 90 Chevy truck 350 TBI with a TPI fuel pump and stock fuel pressure regulator. I have a 4-barrel intake so I am not using the stock truck EGR because it will not fit right I am using one for an 88 Monte SS. The motor feels like it is surging while cruising at a steady speed 60-MPH on the highway I can feel it surging up and down. Has anyone else had this problem if so any clue as to what it might be?

Ronny

iTrader: (1)

Might be lean? I would consider upping the fuel pressure a bit. Consider datalogging to see what is happening with fueling.

91rs5.7tpi

mine was doing the exact same. changed the spark modual and everything is fine

Flip66

iTrader: (1)

I do not have a PC set up for it but I do have a Air Fuel gauge at idle it will hold right at the lean rich point but other wise it is all over the place and never makes it to the rich mark. Do you think an adjustable regulator would help?

I have a bunch of spark controllers laying around so that would be an easy check

Ronny

iTrader: (1)

A/F gauge works as you state. follows the toggle over median 02 sensor voltage. Not of any help but looks cool at night at drive-in. Your reg can be made adjustable. Need to add a guage. Changing the FP is not a tuning practice. More a band aid. Once you set it to an adequate FP to fuel desired WOT A/F you typically forget it and tune from there.

Flip66

iTrader: (1)

Have a pressure gauge but not on yet How do you make the stock reg. adj. from what I read it should be around 16 PSI is that right.

Ronny

iTrader: (1)

stock I think is 11-13. I believe there is a mod done at bottom of unit and then a tool is used to allow the screw to be turned affecting pressure. Is it not in a sticky?