Fuel pump issue?

[302GTS]

Hey, before I pay my mechanic to perform a test to check the fuel pump, I wanted to get some opinions although it seems like a completely obvious issue... I got my electrical system checked out today, and checked off the alternator/battery/starter from the list of repairs needed. That still left me with a stumbling/lean issue. My fuel pump still turns on and runs obviously, but it is definitely a whiner! As far as I know, it's the stock fuel pump, since I've heard upgraded fuel pumps can whine no matter what. Would a fuel pump that's beginning to fail cause a lean condition, along with stumbling, and backfire on acceleration? It's not a timing issue. Timing's good, and has been triple checked, retarded and advanced, and it still backfires. Plugs have been replaced twice in 2 weeks, and havn't fixed the issue. Brand new plug wires, along with a brand new distributor (not remanned!!). Fuel pump sound like the issue?

 

[toyman]

If the correct pressure cannot be maintained to the injectors, yes, a lean condition can occur. Same with a dirty/faulty MAF sensor. If the sensor is misreading the true air flow, a lean condition could occur. For the cost of having a shop test the fuel pressure you could buy a fuel pressure gauge.

 

[302GTS]

If the correct pressure cannot be maintained to the injectors, yes, a lean condition can occur. Same with a dirty/faulty MAF sensor. If the sensor is misreading the true air flow, a lean condition could occur. For the cost of having a shop test the fuel pressure you could buy a fuel pressure gauge.

Checked it from the schraeder valve. It's reading a bit low, but still within stock specs. On a stock car minus exhaust, my mechanic said that's not an issue. However, he said there was a test where he can test the flow of the actual pump itself, where he crimps the return line, and the FP should end up being ~60 psi or so.

MAF has been cleaned, EEC has been reset. I've tried the basic things that I can think of.

Also, months ago, I had the backseats down to carry some rims in the trunk. While driving, the whine was EXTREMELY noticable, if that gives any more insight to the issue.

 

[HISSIN50]

You'd really want to see fuel pressure while it acts up (i.e. pedal matted in 3rd).

Otherwise, I'd rather do a volume test than anything else.

For the time wasted doing all this, I'd rather just get a fresh Walbro and tank grommet and spend the time and resources on that.

Does the car run ok when the car itself is cold and then get worse the longer you've driven it?

 

[302GTS]

You'd really want to see fuel pressure while it acts up (i.e. pedal matted in 3rd).

Otherwise, I'd rather do a volume test than anything else.

For the time wasted doing all this, I'd rather just get a fresh Walbro and tank grommet and spend the time and resources on that.

Does the car run ok when the car itself is cold and then get worse the longer you've driven it?

I won't be doing the fuel pump myself. For something causing an issue of driveability, I'd really prefer my mechanic to knock it out. He's got me some major deals (troubleshooting issues for multiple days, charging me only for parts we try, and no labor), so I plan on bringing my car to him for this problem. I've wanted a FP gauge for awhile, and would like to mount it in the hood cowl. Unfortunately, with the stock hood, I don't know if rain/water/elements would effect it while it's just sitting there in front of the windshield?

HISSIN, you mentioned a volume test. What exactly is that?