I did the fuel filter the other day and it made no difference. (old one was visually clean aswell.)

my ignition on, engine off psi comes up as ~50psi sometimes ( ie: trucks just been shutoff ), but if i turn off the ignition then on again it jumps up to a stable 60psi.

NOTE: this is all assuming that my electric pressure gauge is actually calibrated correctly(wich i assume it is).

 

our s-10 did the same thing except the gauges would sometimes jump to 0 while driving. They said the brake and abs lights can be cause by burning the tires. something about the sensor cant keep up. As far as the bogging, for us it was the fuel pump.

 

it has never dropped to zero {EDIT: i just noticed you were refering to the instrument cluster; those guages all work fine, never drop either}, and this keeps getting wierder to me because. if i say mash up a hill, ill be at 60psi by the time im halfway up but if i let off the pettal itll drop down to ~50psi. if i mash back on it, itll do it again. but on flat ground (hardly any load) no matter how hard i romp on it it just chills at ~50psi.

also the stumbles, rough running, yada yada dont seem to coralate to any fluctuations on the pressure guage. iE: when it stumbles it does so reguardless of whether the fuel pressure is 47psi or 60psi.

So is there any specific tests i can do to tell if my pump is bad or if its a diffrent component?

Ive heard of people pinching off the return line to see if a pump is the problem or the FPR, but our fuel lines are all metal so i dont see that working.

 

could be the fuel pressure regulator

 

Yes, that is what im trying to figure out now; a way to PROVE if it is one or the other, or i suppose if theyr both good. or bad.

 

You could test the dead head pressure of the pump by removing the fuel filter and installing the gauge at that location. Energize the pump and see what the reading is.

You can run down the Fuel pressure test as defined in the Tech Article (DIY) section which should also leave you with an indication of what, if any, problems exist.

 

Just to be safe, and clarify, your saying unhook the inlet side of the filter and leave it unhooked, while i essentially plug the fuel line with my sender? i get what your saying i believe, this would let me see what kinda pressure the pump is putting out alone, right?

Moved from wrong thread:

 

Yes, you connect your gauge to the line that comes from the pump.

 

*Ding* *Ding* *Ding* Gimpy is the winner!!!

...turns out it was a bad wire!!!

 

I just thought I would post too. I had the 100% exact same scenario last week. I have a constant p1406 that seems to be unrelated but that I can't get to go away. At first I thought the bucking was a fuel issue since I had a cold start problem as well. A new pump fixed my cold start problem but the bucking and jerking with ABS and Brake light I thought had to be an electrical issue since lights were flashing randomly all over the dash when it happen. I had already put a new distributor, rotor, cap and plugs in it. Wires were the last thing ignition wise to try and sure enough I put a new set of wires on Saturday and the issue disappeared.

It's weird we were dealing with the exact same issue at the same time. Too bad I didn't see this post earlier. Thumbs up for both of us!!!