Odd misfire question on fuel treatments

[Jgoodson]

My wife drives a 06 with around 120k miles that has had an on and off rough idle for about a year now. As long as there is injector cleaner of some kind in the tank it runs smooth but the minute that tank runs out the misfire and horrible hesitation is back. It doesn't seem to misfire when driving only stopped at red lights I use techron and sea foam as most suggest each yield about the same results. I have replaced the thermostat, cam sensors, spark plugs, and cleaned throttle body and mass air flow none of which had any impact. The cel light stays on no matter what with a p0300 code but as I said within 5 minutes of a fuel treatment the idle is smooth as glass. What do you guys think?

 

[alrock]

Have you owned it since day 1 or did you buy it used? Was the head ever replaced? (That's a worst case scenario, but worth asking.)

 

[USMC_TOP]

My 06 runs a little ruff @ idle if it doesn't have 93 octane in the tank. Have you tried higher octane? I really think if the head was bad it would do it no matter what you put in the tank. For some reason my H3 runs a ton better with 93 octane from Shell or Marathon. Mobil sucks in it as does Citco and Speedway gas. I wouldn't worry about it and run an additive like your doing or try other fuel companies.

 

[alrock]

I went the head route because it was there was a pronounced performance difference between good gas and cheaper gas, though not immediate like the OP said. Mine would show up after a tank of the cheaper stuff or w/o Techron in the tank. Maybe it's a fuel issue, like a failing pump or clog, that is apparent at part throttle but not when wide open, like a partially clogged aperture. Just a wild guess though.

 

[Airborne]

I would guess ignition coil packs. Those are easier to replace than spark plugs. Would be worth a shot.

 

[USMC_TOP]

Just curious, what exactly fails on the 06 head? Crack in the combustion chamber? Bad valves? Cams? A crack should show it's face the hotter the engine gets due to expansion right? I hope good fuel fixes your issues bud..............ALROCK I was second guessing you @ all brother. If my head goes on my 06 I will for sure find myself a 07 3.7 to go in it. I have 87k on mine with no dealer head work, I know that much for sure. Doesn't mean someone else didn't replaced it though.

 

[DaWgPoUnD]

Sounds like coil packs or a vacuum leak. Replace all 5 packs and check for leaks.

 

[Hayden]

Valve seats are what fails if i remember correctly

 

[USMC_TOP]

Thank you Hayden!

 

[USMC_TOP]

Maybe a lead additive would help........

 

[alrock]

Didn't think you were second guessing me at all. Lots of different answers here and I was just clarifying mine.

Sent from my SM-N900V using Tapatalk

 

[Woodtick]

Sounds like chit gas to me!!! The best mod I have done to my H3 is corn free 91 Oct. My 2013 2500 doesn't like the Chicago/ summer blend. The truck falls on its face at start up? The winter blend doesn't effect my work truck at all? The EPA knows best,ask them why your rig runs like chit,and gets horrible MPG on that chit fuel they are forcing on us?????

 

[Jgoodson]

Sorry I have been on vacation this week but no I have not owned since day 1 bought used around 60k miles, I have tried all different kinds of gas premium and also ethanol free for about 6 months straight no difference between them very noticeable but 91 octane ethanol free with a bottle of techron gets a little better mpg, it doesn't make any sense how it could be an electrical issue if a bottle of fuel cleaner makes it go away, what about a bad o2 sensor code?

 

[alrock]

P0300 is a general misfire code with a lot of different causes. Usually if it's a particular cylinder it will be P0301, P0302, etc. with the last digit indicating the faulty cylinder. I think the coil was suggested as maybe if it is underperforming, you are not getting the full performance from it but somehow the fuel cleaners are helping.

Maybe it's bad fuel injectors?