I have a 1998 ford f150 4.2 l engine that has intermittent fuel issues I have been to the local dealer 6x and they still give me the we don't know what is wrong with it answer. when I start the truck seem to have a long crank time, when the truck run it runs awesome no issues, when its running rough at idle I can sit in the truck and make margaritas the truck shakes so bad, engine seems like its stalling oil pressure gauge is all over the place. hearing a ping when I give the gas a hold. let off of it after this and let it decide what it wants to do never resets. I depress the gas and don't get any revs only letting off do I get any revs. I have to pump vehicle to get some speed at stop signs truck moves to a crawl, I turn the vehicle to reset and truck will start as if nothing happened. I also hear the fuel pump from inside the truck at start up and under the truck when its running fuel pump sounds whinny but not sputtering or and weird sounds when running rough, I have had the changed spark plugs wiring harness engine coil, fuel filter had a oil and fuel compression test done and am running out of ideas on what to check so needless to say I do not want to go to my local ford dealer as they lost my keys already broke my trim for a window install and when chaged out ignition left all the part all over the truck and also each time I go to the dealer they never fix the fuel problem I asked them to fix any help would be good or ideas

 

Sorry your having such a time.
It is difficult to get a lead from your descriptions but I would be looking first at the EGR system for the EGR being held open.
This will cause rough running, possible ping and stumble.
Try the following.
Find the EGR valve and remove and plug the vacuum hose.
Start the motor and see if the idle is now smooth's out and drivability becomes normal.
If yes, remove and clean the EGR solenoid regulator and it's filter under the round cap that the hose connects to. It is sticking open and allowing vacuum to open the EGR.
Good luck.

 

I have tried the egr taking it off while started when running rough with no change to what's happening with the truck

 

I also just changed the tp sensor as a code came up for it but ran the truck and seem good for awhile and then truck goes back to shaking no gas when depress gas get some if I ease up on the gas pedal and back in return position like I said I checked egr tp sensor changed cables and plugs fuel filter the fuel pump is working can hear it running when truck running I only get the ping sound if I press gas in down position for three seconds I have code reader hooked up every time I drive in a chance to find some intermittent code but nothing even with new tp sensor sometimes get it coming back up also wonder if 1500 is a lot to pay for dealer finding a lot if nothing just putting parts on basically

 

This is difficult to get a handle on over the internet.
Be patient and run with my attempt to help you.
It you are sure you hear pinging, with rough running and loss of power,
it suggest the EGR is stuck open.
Only way is to remove it for leakage test or slip a blocking gasket between it and the mounting flange temporarily and remount for test to verify the leak if motor smooth's out. If no help it is not the problem.
Lets do one thing at a time to try to pin it down.
Check the fuel pressure with a gauge on the test port to verify fuel pressure is correct at about 35 psi +/-.
Good luck.

 

I have had the egr off and tested the fuel pressure and is sitting where it should be I also test oil pressure and is sitting where it should