3.8l Engine: Random Misfires, Inconsistent Codes

Gray · Feb 22, 2019

01yellercobra said:
IMO no there isn't.

Thanks, appreciate it!

Gray · Feb 23, 2019

Okay... I jumped the fuel pump again just to see if my reading is consistent. It puts out a steady 75psi when jumped @ 12v. I let it sit there for 15 seconds and watched for deviation - it remains constant, no dips.

Since it can maintain that pressure @ 12v, does that tell us anything? I can't find the specs on OEM fuel pumps to determine what the fuel pressure should read at various voltage... if anyone has that information, I would be very grateful.

Gray · Mar 1, 2019

Hey guys, still no luck with a resolution. I even broke down and paid a website to contact a ford mechanic, and so far he's not been much help. In fact I'm beginning to suspect that he doesn't actually know much about this system or vehicle. His suggestion was to replace the entire pump assembly - his claim is that there exists a 'fuel pump transducer' as part of the assembly. I cannot find any trace of such a thing anywhere. The only sensor that Ford even mentions (this includes a very thorough search through various supply catalogues and troubleshooting guides) is the fuel pressure sensor on the fuel rail.

At this point, the only piece of the fuel delivery system that I have not replaced is that damned sensor. Do they typically go bad without blowing the diaphragm, and if so, what are the signs of failure?

wblynch · Mar 4, 2019

Did you ever replace the IAT? I have a 97 that runs erratically at times then smooths out after reaching temperature. I replaced both water temp senders with no resolution and after reading your top post I am wondering if the IAT sensor is the culprit.

Gray · Mar 8, 2019

Hey guys, I just wanted to drop by and fill everyone in on the resolution. After all this fighting with the fuel delivery system, it turns out my computer was sending me misleading codes. Fuel wasn't the issue, SPARK was.

My coil pack was bad. I went and talked to a local mechanic, was going to drop off the vehicle and have him look at it. He wouldn't check it in until I replaced the coil pack. He says - "if it's still giving you trouble after that, I'll take a look." Fifteen minutes later in driving back to his shop to kiss him on the mouth. He settled on a handshake, but still, extremely grateful for the suggestion. I cannot believe after all this it came down to such a stupid, overlooked part.

Thank you to everyone who has contributed and offered suggestions! You are all very much appreciated. I don't know where I would have been without your assistance. Cheers, everyone. See you next time.