I’m new to the group and I haven’t been able to find this exact issue covered. Apologies if I missed it. I’ve got a 1998 F150 with a 4.6 single cab VIN W 4x4. Truck would run fine for X amount of time, then studded and act like it was choked and die. Try to start again and it turns over fine and almost try to start but won’t. Let it sit for an hour or so and it will start and run fine for X amount of time. There is NO exact amount of time it will run. It’s very sporadic. So far I’ve changed plugs, wires, coil packs, CSPS, IAC Valve, EGR Valve, TPS, ECM, air intake temp sensor. Vacuum hoses off the air intake tube (x2), booster to intake, A/C Vent Valve vacuum line from pass side of intake. I have cleaned battery posts, grounds to the firewall and intake. Have fuel pressure at the rails. Any ideas?

 

Change the fuel filter.

 

I changed it about 4,000 miles ago. And it’s only throwing codes for O2 sensors. No cats.

 

You got a diploma in shot gunning with a load of parts that did not fix anything but empty the wallet.
A Scanner to look at the operating info is needed to diagnose the fault.
What are the Long Term Fuel table values?
What is the fuel pressure ? with a gauge when the motor stalls.

 

While running or when it’s acting up, there are not any codes. Everything reads normal. Last week it wouldn’t even read the ECM. I spent money on parts because they needed to be changed anyway. And fuel psi is enough to put your eye out right after the truck shuts off. So you can keep the smart*** comments to yourself. The ford computer wouldn’t read the truck. So why do you need diagnostics when there aren’t any??

 

Well you can't handle the problem and i'm a smart *** after 14 years and 321k miles of owning these motors and race them in SCCA competition.
What would I know about anything?
Good luck.

 

You just shot yourself in the foot. Bluegrass is one of our most knowledgeable members.

You say it's throwing O2 codes, then you say it's not throwing any codes. Make up your mind. If it's throwing codes, post the exact codes. How many psi is enough to put your eye out? Need numbers.

 

Sounds like a fuel problem. Could be the pump, filter or regulator. What fuel pressure are you getting ? Have you checked the regulator ? Are you using Motorcraft filterrs ?

When did the problem start ? Was it after getting new fuel ? Has it been gradually occurring or just suddenly begin?

 

Your PCM may be going out or the connection to it. Or possibly one of the block connectors near the battery on the firewall are loose. Sounds like your loosing pcm signal somehow. Yea you kinda screwed yourself standing up to bluegrass. That dude is one of 3-4 members on how I know everything about 4.6 and 5.4 2v and 4v. Also, the reason a huge amount of us can get back up and running. I know you may have took offense. But the senior guys don’t take bull**** nor out to get anyone who don’t ask for it. Intentionally or unintentionally. Keep us updated! My sister had a pt cruiser do that. 3 Chrysler dealerships couldn’t find problem after replacing damn near the whole car😂