Jason's 96 F150 5.0

[rubydist]

I would put some Motorcraft semisynthetic oil in it and take it on a 3 hour drive. I have had great experiences with loosening stuck rings and removing varnish from lifters by just using that Motorcraft oil and making at least half hour drives regularly for a couple months. I would do that and see what happens before I tear into the engine, because these engines at 200k miles typically still have crosshatch marks visible on the cylinder walls.

 

[superj]

i always used transmission fluid in the crank case to clean stuff up inside the engine. than change the oil twice and it will be good to go

 

[ford4wd08]

I'll confirm the fuel pressure first tonight then move on to check other items that for the DTC to begin with.

It does make some noise in the valve train. Could be because it doesn't have many miles on it, must have set quiet a bit over the years.

 

[ford4wd08]

So, knock the fuel pressure off the list. Key on non running it is 30 psi, fuel pressure regulator unplugged it is 40 psi, with it plugged in it's right around 32 psi. I believe that's inspect for this year 5.0?

I put a vacuum gauge on it and was reading around 14 to 15 " of mg. My gauge said late timing, so I figured why not adjust the distributor a little to advance the timing. With a warm engine, spout unplugged I advanced it slightly and jumped to 18 - 20 " of vaccum. It is difficult to see the timing marks on crank, the PO had put marks on it, but I think they were slightly off. This seems to be the correct setting of 12 degree BTDC. Plugged spout back up and it was running slightly better. Still a bad miss when under load though.

So what is next? I'm thinking it could be a vaccum leak, but I can't prove it. Sprayed around intake with no difference in engine running. I don't think it is internal to engine as it wouldn't make that much vacuum if there was a problem would it?

I also listen to bank 2 injectors. I can hear them firing or ticking.

I checked grounds today also. All looked good.

Not sure where to go next? What else could cause a mean mixture code for bank 2 and cause the missing condition?

@RonD @19Walt93

Oh and I checked EGR with vaccum tester. It pulled and held vaccum no issue.

 

[RonD]

A misfire causes the Lean code on that bank
O2s only "see" Oxygen not fuel, so "lean" code does not mean lack of fuel, it means too much oxygen, which is different

When a cylinder misfires no Oxygen is Burned up with the fuel, so both are dumped into the exhaust manifold
O2 "sees" higher oxygen on that bank so shows Lean
Computer responds by adding a bit more fuel to that bank, which can make things worse if misfire was from weak spark, lol
If misfire continues then computer sets lean code because what it tried didn't work

So Lean code is rarely the cause of a misfire, its a symptom/result of a misfire

If it was a vacuum leak then there probably wouldn't be a misfire, because computer would have added more fuel to compensate for the extra air, so just the lean code, but engine running fine

 

[19Walt93]

I've never seen a misfire set a lean code, only a rich code, unless there was a plugged injector. I'd suspect a vacuum leak.

 

[RonD]

How would a misfire set a Rich code?

O2s can only see Oxygen

 

[scotts90ranger]

I'm with Ron on this one, misfire causes extra oxygen in the exhaust, seen it fairly often at work.

Changing the oil and running it won't help things unless it's a gummed up lifter (which I wouldn't rule out...). On that note, might be worth pulling valve covers to check that all valves are at the same height and eliminate a broken valve spring or something...

 

[superj]

was your vacuum gage holding steady or jumping around? 18-20 is pretty decent. use your vacuum gage to set time instead of using them arks and it will be better. than the timing is set to your engine, not to a generic engine setting.

Vac Visual: Quick Guide to Vacuum Gauge Readings - OnAllCylinders

setting time with vacuum gage
Vacuum Engine Timing | MILEPOSTS Garage (Tech Tips) (automotivemileposts.com)

 

[ford4wd08]

was your vacuum gage holding steady or jumping around? 18-20 is pretty decent. use your vacuum gage to set time instead of using them arks and it will be better. than the timing is set to your engine, not to a generic engine setting.

Vac Visual: Quick Guide to Vacuum Gauge Readings - OnAllCylinders

setting time with vacuum gage
Vacuum Engine Timing | MILEPOSTS Garage (Tech Tips) (automotivemileposts.com)

Vaccum held steady. No jumping at all. Got it over 18" of hg. I think long block is healthy minus something stupid causing this miss.

 

[ford4wd08]

I'm probably going to throw in a towel on this one and take it into a shop. When the old Ford dealer closed here, one of the top service guys opened his own shop. He well regarded when it comes to working on Fords. I think I'll let them have a look at it.

 

[ford4wd08]

In case you guys were on pins and needles over this....

It ended up being a failed lifter and bent pushrods.

How that happened, I'm not sure I'll ever know.

The shop ended up replacing all of the lifters and pushrods with a couple of other odds and ends. Runs very well now.

I still could sell it and make some money on it but we will keep it around.

I had to move some furniture the other day and it was an absolute pleasure to have a 8 ft. bed that was low to the ground.

 

[dvdswan]

Overrevving and floating valves.