P0305 code and too lean

[X5rdman]

So i did have the p0305 and the too cool code registered. The thermostat did need changed. So here is what i did.

Changed the thermostat, btw, whoever designed the lower alternator bolt location should be fired.
New plugs, properly gapped,
Cleaned throttle body (2 time in 6 months, so it really shines)
Switched the spark plug pack from cylinder 5 to 2 ( not sure the real name)
Had the battery disconnected for more than 6 hours.

So run the car for less than 30 miles and now the p0305 and another code for too lean came on. Any suggestions as to what i should try next? I can feel the missfire at times, so i know it is real. I may just take it to the dealer, but thought i would see if there are any other ideas first.

Btw, thanks to all the stickies that got me through everything i already did.

 

[signalnc]

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[signalnc]

what plugs did you install? The 4.2 really likes the delco iridiums. I think it's a part number 41-103.... it is also possible for you to have a valve issue. Maybe someone with more experience can better assist with that.

 

[Opeth]

Check your intake manifold bolts, see if they are loose. If they are only hand snugged you could have a seized valve and you don't want to know what that requires to fix it.

You ruled out a bad coil/ plugs. So it's either the above or a fowled out injector. Go buy a couple cans of sea foam and start there.

 

[signalnc]

I've never tried it but someone said bg 44k is good also. I think you have to order it online. Sea foam is available in the store. Just follow instructions and add the amount into the fuel tank.

 

[X5rdman]

Ok, checked the intake bolts, and they were seriously loose. So i tightened them up disconnected the battery for a bit, and took a drive. Light came back on, then went for another short spin and light went off and running god. So maybe issue is solved, will know after a few more days of driving.

How do those intake bolts get so loose?

 

[Voymom]

Did you switch JUST the spark plug from cylinder 5 to 2? Or did you switch the coil pack and spark plug to rule the coil pack out?

You should switch the coil pack and not just the spark plug in order to properly rule out the coil pack being bad. We just had this very issue on my husband's TB. It was a very easy diagnosis and an even easier fix.

44k is a great additive as I have used it, you don't have to order it online, I found it at the local oil boys oil shop down the road. Most dealerships don't sell it unless you buy their stupid injector cleaning crap as well that they bend you over for in labor costs. I like sea foam because it can be ran in the fuel, oil and the other place which I just forgot due to a giant brain fart

 

[CaptainXL]

Ok, checked the intake bolts, and they were seriously loose. So i tightened them up disconnected the battery for a bit, and took a drive. Light came back on, then went for another short spin and light went off and running god. So maybe issue is solved, will know after a few more days of driving.

How do those intake bolts get so loose?

Probably no thread locker. The intake bolts have a specific torque sequence in inch/pounds not foot lbs. So you really should back all of them off and start over with the proper sequence. Which brings up the point that if the gasket was leaking then you would have dirt contamination of the gasket surfaces. So what I would do is take off the entire manifold and get a new gasket and do the proper torque.

 

[X5rdman]

Voymom, i replaced the spark plugs about 10k miles ago, i just switched te pack to rule it out afterwards. Drove again this morning and running great now the intake is tight. I will probably take the time in a week or two to change out the intake gasket.

 

[X5rdman]

Ok, still working on this issue. It keeps coming and going, the P0305 code, the lean code is gone. But i have noticed something more than once now and want some feedback. When i fill the tank the missfire immediately goes away and gets stronger as the gas level decreases over the week. So is there a chance that part of the problem is low fuel pressure and the full tank is helping drive up fuel pressure?

 

[CaptainXL]

All of the following will need to be checked.

A code P0305 may mean that one or more of the following has happened:

•Faulty spark plug or wire - Did you replace the plug?
•Faulty coil (pack) - You swapped the coils so this is not likely.
•Faulty oxygen sensor(s) - Did you replace the O2 sensor at 100K miles?
•Faulty fuel injector - Perform a fuel trim injector balance test
•Burned exhaust valve - Perform a leak down test
•Faulty catalytic converter(s) - Perform an exhaust pressure test
•Running out of fuel - The computer will ignore misfires if it knows this
•Poor compression - Perform a compression test
•Defective computer - Unlikely

 

[X5rdman]

Ok so broke down and took it to the dealer. Compression was good, fuel injector bad and cleaning wouldnt fix it so......i paid got it installed and runs like new. Guess time will tell, but 50 miles and running strong.