Urgent help needed. poor run condition CODES ADDED

[mavrick1903]

turning 65-70mph down I-94 this AM. had an OBD2 connected. truck started running rough (prior threads by me will indicate other discussions around things not running well, hence having the OBD2 handy). so:

Running badly. turn off OD, RPMs kick up to 3k, runs better, but not great. with OD on, much worse. this condition does creep along with me though, and before long running with OD off is not running great, but still notably better than with OD on.

Errors: System too lean (bank 2)
followed by: Missfire, cylinder 5
followed by: System too rich (bank 2)

I have replaced the air, and fuel filters, tried seafoam in the tank to try to clean the injectors (2 cans in a tank less than 1/4 full). I've also replaced the MAF sensor after cleaning did not seem to help. the MAF was what the shop told me a while back would fix the engine light. it obviously has not.

What's next?

I've checked (by spraying MAF cleaner) for an intake gasket leak, but that does not explain some of the other issues. Bad computer? Thoughts? Help!?!

To add to the fun: I'm 75 miles from home (and tools). I think I can get it home if I need tools though...

 

[ragajungle]

lean then rich? hmmmm. does it idle erratically or especially high? if so maybe a vac leak..

running rich maybe a bad FPR

I would post codes when you get a chance.

 

[mavrick1903]

Erratically, not high though, low.

I dont have the numeric portion of the codes off hand (was driving).

What's a "bad FPR"?

 

[ragajungle]

FPR= Fuel Pressure Regulator.

When they go it dumps excessive amounts of fuel cause rich running and sometimes flooding and gas in the oil.

 

[swetrid]

Start with fixing the cylinder misfire. If it is running rough it can give you rich or lean codes depending on whats causing the problem.

 

[mavrick1903]

Good advice, but where to start?

 

[2000StreetRod]

Good advice!

Start with fixing the cylinder misfire. If it is running rough it can give you rich or lean codes depending on whats causing the problem.

Misfire is normally due to ignition, fuel injection or compression - in that order.

Ignition:
1. replace the spark plug (especially if its Bosch double platinum) While the plug is out check the compression.
2. test the spark plug wire with an inexpensive spark tester

Injection:
1. Use a mechanic's stethoscope, section of hose or rod to listen for regular clicking of injector
2. Purchase a noid light and test pulse to injector

Compression:
You could have a blown head gasket, cracked head, weak or broken valve spring, bad valve seat or worn/burned valve.

 

[mavrick1903]

Here are the codes I have:
P1150 lack of HO2S21 switches fuel trim at limit.

P0304 cylinder 4 misfire detected

P0175 fuel system too rich (bank 2)

I have also seen a bank 2 too lean but don't have the number, likewise for a cylinder 5 misfire. All of these are today.

It would run better for a time with OD off, though I'm worried about causing transmission issues if I keep that up.

 

[storlied]

Change your plugs and FPR.

 

[mavrick1903]

Checked (now home) P305 and 306 as well, cyl 5 and 6 miss fire

 

[ragajungle]

def check that FPR if you are getting misses and rich codes all over the place...