Newish first gen lightning owner. I picked this 93 up over the winter and didn’t get to drive it much till recent. For the first couple months it ran great. It has a rebuilt motor in it with original heads and intake. Recently it has developed a few issues that may or may not be related.
First issue is that it starts up fine when it is cold, but after it warms up if you shut it off it idles rough to the point that if you don’t rev up the rpms it will stalk out. After about 30-60 seconds of keeping it at a high idle it will smooth out and stay running.
After that the truck seems to have poor acceleration/loss of power and hesitates when you apply throttle to the engine.
It’s been doing this for awhile and unfortunately I’m currently waiting for a tow truck because it died completely on me and won’t start back up while I was test driving it.
It just shut off while accelerating and cranks but doesn’t fire.

Here are the things I have replaced.

-New battery and all new cables, including grounds and starter cable
-tps sensor
-new plugs, wires and cap & rotor
-new speed sensor

I’ve checked all of the fuses in cab and under the hood. I ran the scanner on it and no new codes, just the codes it’s always had because all of the pollution crap has been deleted.

Any thoughts or advice would be greatly appreciated. I’m not a mechanic but I’ve been working on my own vehicles my whole life and can figure out almost anything if I’m pointed in the right direction.

Thanks in advance!

 

Turn the key over and listen to see if the fuel pump runs for a few seconds. If so, you can put a Fuel Pressure gauge where the shrader valve is located on the fuel rail. A healthy fuel pump should yield around 28psi at idle and close to 40psi with the vacuum line removed from the regulator, with the engine running. Also, if you have a scanner, check for codes.

 

If it's got Mass Air, check to see that the sensor is plugged in. I replaced the one on my 96 E150's 351 last weekend and it acted the same way when it was unplugged.

 

If it's got Mass Air, check to see that the sensor is plugged in. I replaced the one on my 96 E150's 351 last weekend and it acted the same way when it was unplugged.

 

Could also be the crankshaft position sensor.... and they can fail ...even a loose wire connection that will not always throw a code......….that would also make a no-start sit.