4.0- P0306 Falt Cy G, MSFR DET Cy 6

[Shotokan1509]

EDIT: See post #6, had fixed original problem few months ago, now different cylinder misfiring.

Rough idle, check engine light is on, flashes under load but runs ok. 95 4.0, code is P0306 Falt Cy G, MSFR DET Cy 6

Plugs and wires are year old/10,000 miles. I have had a few times randomly that it does not like the quick restart when warm.

Few things from searches I think I should check (and would these only affect one cylinder?)

MAF: I can clean it, is there a way to test it?

IAC: is there a way to test it?

Coilpack: does coil fires 2 cylinders at a time? If yes, anybody know that other cylinder that is matched with cylinder 6? Figure clear the code, swap the plug wires and see if its still 6 as the misfire, or if it changes to that matching.

 

[Nhaz]

the IAC is easy to test. unbolt it from the truck 2 bolts. apply 12 volts dc to the leads. its a basic solenoid if it works it will slip back and forth with the volts are applied.

 

[Shotokan1509]

Cleaned the MAF, IAC, PCV and put a new airfilter on it.. then cleared the code. The light did not come back on, but the my tuner read a new code P1000 which I can not find in any of the lists. Still stumbles, it seems to idle fine in park, but hates sitting in drive/reverse at a stop, runs decent with my foot in the gas but not perfect. I did check the throttle body, looked clean. Going to try some injector cleaner in it, but need to put more gas in the tank first.

How would I go about testing the coil?

 

[naford]

This code says the care/truck hasn't gone through it's test cycle yet. It should be off if not it menas there might be something else wrong.

 

[Shotokan1509]

Seemed to be plugs, now I'm thinking it was 2 summers ago that I did them. They were worn funny, like one side was more gap than the other. Oh well, hope this was a simple fix. I gotta tell ya, this time doing the plugs was MUCH easier than last time.

 

[Shotokan1509]

Misfire Cylinder 4 now, pulled the plug looks ok, tried swapping plug wires with another cylinder and still misfires on 4. Have maybe 3,000 miles since last misfire issue, what are other quick checks or something that might affect cylinder 4 more than another cylinder to show an overall issue?

 

[graff104]

possibly a bad injector? First that comes to mind besides plug and wires when talking about just 1 cylinder.

 

[Shotokan1509]

possibly a bad injector? First that comes to mind besides plug and wires when talking about just 1 cylinder.

I did put some fuel injector cleaner in it, that's not to say it can't still be clogged or bad.

Bit more info:
Sometimes starting the truck is really rough, others no problem
Sometimes it will idle in park fine, but get cranky in drive.
Hills are hit or miss, light throttle the same.

Yesterday I swapped plug wires around, cleared the code and drove 20 miles or so, easy flat cruise, steep hills, highway and it ran fine no code. Parked in the driveway, went to move it 30 minutes later and it started misfiring as soon as I started it Even the misfire is inconsistent, sometimes I can barely hear/feel it, others the entire truck shakes/chugs.

 

[tdog]

i hope this is not your case but I have worked on quite a few that a head gasket leak would cause an intermittent skip, especially after sitting. What happens is a small amount of coolant will leak into the cylinder and cause a misfire, after a few minutes of driving it will clear up. the easiest way to check is to look at that plug and compare to another one. A good one will have a brownish/gray tint on the end while a greenish/yellow tint will be on one with traces of antifreeze.