System to Lean Bank 1 & 2 and Cylinder 3 Misfire.

[96mustangV6]

Well my truck threw a misfire this morning on cylinder 3. But for last couple months its also thrown code p0171 and p0174.

Some think its a intake gasket and not a plug or coil causin the miss fire. I've replace a lot of the elbows and vacumm lines. Even the elbow on back of intake. Is there any ways or tricks to do vacumm test with out truck running to see if lines or intake gasket are leaking. I really don't wanna do plugs if I don't have to. Kind of worried lol. Its a 98 navi with bout 220k miles but was rebuilt before I bought it. Its drove fine for last few months with the lean codes but just started kicking this morning and threw the miss fire.

 

[JUST4FUN]

wonder if the mass air flow is bad,just a stab in the dark thou

 

[96mustangV6]

On way home from work I stopped and replaced the pcv valve and 2 more elbows. I've been chasing the lean codes for months now. But never affected how truck ran. Then this morning on way to work it started its studdering then light started flashing. So I hooked up my obd bluetooth reader and cylinder 3 MissFire popped up now. So after PCV valve I reset light and drove home. Bout 10 miles. It did its flashing again and just showing Cylinder 3 again. I'm hoping I don't get the loan codes again. But who knows.

I'm thinking bout changing coils on #2 & #3 and see if it follows the coil pack or not. Kind of hoping its the coil and not plug.

 

[jbanks]

I'm just throwing this at the wall to see if it sticks.

When I replaced my fuel filter it cleared up my lean codes.

 

[FordandPolaris]

Coils are a good place to start. My guess is that it is two different issues at this point. Switching the COP's is an easy test though.

A clogged fuel filter would cause a lean condition just because the fuel does not push through efficiently. Its a cheap part to replace and should be done anyways, so that is a good place to start if you have ruled out the PCV elbow on the back of the intake.

 

[96mustangV6]

I forgot to mention that I replaced fuel filter bout a month or 2 ago. I guess after I get this coil or plug fixed I'm going to buy MAF cleaner and clean it.

 

[hwy73]

1st Gen were known to leak from a heater hose "T" fitting and drip coolant onto one of the COP's at the back of the engine, taking it out. Just something else to check.