EDIT-38k miles!
2000 3.0L
Getting only one code for P1131 HO2S B1S1 switching lean
Missing on cylinders 1,2,3 (not aggressively no codes for missing)
Visually confirmed with scanner.
New wires, checked plugs and gaps (tried new coil), new fuel + cleaner, smoke tested, checked injector resistance from pcm wires, followed a test plan, check compression, and checked fuel pressure. Cleaned the MAF sensor. Pressure goes to 60psi when initially turned on, then after a brief second i hear a click and it drops down to apx 52psi. Leak down tested good.

ergh... Help please??

 

Welcome to FTE.
I see you don't have any replies yet, so I'll see if I can get things started.

Any idea what is clicking when the psi drops?

Seeing as how it seems only one cyl bank is affected, you may have more than one problem.
Were all those parts bad, or scheduled maintenance time for their replacement, or were you just tossing parts at the problem & hoping for joy?

It's not clear how you were viewing the miss on a scanner. What kind of scan tool & diagnostic software were you using?

Did the problem come about slowly over time, or suddenly after some event?

Some beginning trouble shooting thoughts consideration & questions to try & get a mental grip on your situation. SO, more input would help.

 

Thank you for your response.
The pressure check was fuel, i forgot to note that.

The only new part is the plug wires. The plugs were checked and gap'd at .44. Coil pack was just a try me out cause i didnt have a spark tool.
I have a Snap-On Solus Ultra that i can view cylinder misfire using the "Cylinder Contribution".
When i first got the truck it didnt run like this. It sat for a month until i got started with some body work, now that im done its acting up.

The clicking sound im going to assume was the fuel relay, but ill have to confirm that.

 

OK good feedback. When doing the fuel pressure test, did you also perform a volume over time flow test? It should be something like 1/2pt-15seconds.
If flow volume is wimpy, since this puppy sat a while & past scheduled maintenance seems unknown, when last was the fuel filter changed? A clogged fuel filter can mess with volume & pressure.

 

Believe it or not, i was doing exhaust work over there as well, just re sealing the manifold to the y-pipe, so i decided to just throw and O2 sensor at it and now its reading properly with no misses.

Crazy!!!

Furthermore, i find it crazy that the test plan didnt have me actually check the o2 sensor and had me doing all sorts of stuff just for it to tell me to do the pcm. I figured O2 is way cheaper!

Anyways, thanks for you help.

 

Ok, good find, fix, feedback & to hear all now seems well & your on the road again.
If during the exhaust work that puppy got a whiff of the wrong rust buster, silicone spray, or coolant, it'll take em out pronto.