93 4x4 Pickup chokes under acceleration
 

I've searched and searched and can't find any info on the exact issue I'm having with my 22R-E. I recently experienced an issue with the engine losing power when I gave it gas, hard starts, and the issue was getting worse. Going on what I learned back in high school with the 89 pickup I had, I know it has to be with the fuel delivery system (same sort of issue I experienced then). I have a new fuel filter to begrudgingly replace, and a new fuel pump on the way.

Here's the part that's got me completely baffled: with the relay pulled (passenger kick panel, above the AC/heater fuses and computer) THE TRUCK STILL RUNS. I need to depressurize the lines, and can't figure out why it's still running with the relay pulled. Is that not the correct relay or am I missing something? I just filled the tank not 2 days ago, otherwise I'd have dropped that sucker and pulled the pump.

Yes, hesitating when accelerating sounds like fuel starvation.
But what relay?
If you could not be sure of what's in front of you, how could we be?
A picture paints a thousand words.

https://cimg5.ibsrv.net/gimg/www.yot...0436a3c985.jpg
That relay should be for the pump I think.

I'm away from my pix, so I can't send you one of a COR.

But pulling the COR is a waste of time anyway. Liquid Gasoline is incompressible. When you open the fuel filter connection, you'll get about a teaspoon of gas. Use a paper towel.

What you do need to do is remove the gas cap. On a warm day the fuel vapor (very compressible) can push out a few gallons.

By the way. Check your ignition timing.

I hadn't thought about the gas cap. That makes total sense. Probably why the fuel rail in my Porshe 924 Sport blew fuel everywhere when I pulled everything down to the deck. Thanks for the tip!
As for the ignition timing, I'm fairly certain I need to replace the chain, guide and tensioner, but I had planned to do that in the spring when I got around to adjusting the valves. I'm sitting at just shy of 190,000 miles, and I doubt the PO ever serviced the timing chain or the valves. I hadn't considered the timing at all. I'll make sure to check it while I'm at it.

IGNITION timing. With a timing light. Sufficiently retarded ignition could give your symptoms.

It appears that I've got good spark and ignition timing. The plugs look good, however, the weather does not. I'm crossing my fingers that it's the fuel filter and not the pump or injectors. I'm not entirely sure what I'm going to do with a full tank...

The fuel filter was indeed no bueno. After cramming the new one in, I've got better starts and idling along with more power. Time will tell if that's the entirety of the issue, but today is a good day.

If the fuel filter clogs odds are the fuel pump "sock" has died. *subtext, don't leave that new fuel pump sitting around collecting dust*

You can get a hand pump siphon system at the local part store. And of course sucking down a mouthful or two of fuel is a mechanic rite of passage from the dawn of time..

You can also change the filters on the injectors for about $20-30, another five or ten to fully service them with a cleaning if you do it yourself.

Do the volume test scope and others have documented, pull the return line off the regulator and plumb it into an empty two liter. Do one test before the pump service and another after and you'll be able to quantify the difference better than the old butt dyno.