P0300 code

[Kpc01]

I pulled one of the rubber boots off a coil, and low and behold the inside was covered in rust, so far I have managed to clean 5 of them and replace one. I will eventually will replace all, after I see if this might have been the cause. Thoughts???

 

[Redtruck-VA]

Water and rust would certainly give you a misfire. The rust must be coming from the springs inside the boots. I would guess the boots need to be replaced before you really solve the misfire problem.

 

[Kpc01]

Thanks, I hope I am on the right track, my inspection is up this month.

 

[RonJon '06]

If you put a good coat of dielectric silicone grease on the inside of the boot that will keep moisture from getting inside in the future. Glad to see you figured it out.

 

[xb1230]

Focus on Cylinder 3 and 5 as they are the ones giving missfire codes from your Torque pro report.

Also I would have a closer look at the Bank 1 Sensor 2 O2 sensor as 1 of them is not reporting and the other even though within spec is on the low side.

If you have the $ it might be a nice thing to get new ones. Give a good look at the wiring and see if any of the wires are cracked or even broken.

Keep going you are ont he right track.

 

[Kpc01]

Thanks for all the feed back, I will make new changes today and report back.

 

[03MopaRamman]

I get the P0300 when my tank has fuel injector cleaner in it and the cleaning process is ongoing, after i refill and carry on it normally does not come back. But i am running a new cam on superchips as well so for me it could be just an inherant problem thats tuning related but in the past it tells me my injectors where dirty and being cleaned off. Once you get the wiring and 02 sensors confirmed as good to go it wouldn't hurt to run some FICleaner through as well. Danny

 

[Kpc01]

I have been running some seafoam in mine, the past two tank fill ups this tank no cleaner. I think the wiring and o2 sensors are fine. I changed the ignition coils on cyclinders 3,5,7and 8, they were the worst. Going to change the rest next weekend. Thanks again for the feedback.

 

[Kpc01]

Anyone have any ideas on why I would now be getting a P1128 code?

 

[Redtruck-VA]

I read that as running in open loop, my guess is you have a loose O2s connector. When you move things around you need to go back over everything that was touched or moved to make sure nothing got knocked loose or up against something hot. Check the MAP connections.

 

[Kpc01]

Connections look good, think I will replace the IAT and Map sensors, couldn't hurt.

 

[regularcab2500]

you dont have a 6.4 hemi do you lol? mine did that at 1200 miles and it just needed a pcm update

Sent from my SCH-I510 using Tapatalk 2

 

[Kpc01]

No, I have a 5.7, just hoping the dealer is not right on needing the heads redone.

 

[Redtruck-VA]

No, I have a 5.7, just hoping the dealer is not right on needing the heads redone.

Have you done a compression test? That'll give you some idea of engine/head condition.

 

[Kpc01]

No, dont know how.

 

[Redtruck-VA]

No, dont know how.

Do you have the needed tools to change spark plugs?

 

[Kpc01]

Sure do, I changed them and the ignition coils recently.

 

[Redtruck-VA]

Sure do, I changed them and the ignition coils recently.

Ok, good. Get a compression tester from your local parts store and read the instruction on how to test for cylinder pressure. Basically remove the fuel pump fuse, prop open the TB blade, remove a plug from each cylinder, screw in the tester. Turn the motor over 3 or 4 times and record the pressure on the gage. Should read 160 psig. If they are al relatively the same then the heads/cylinders are healthy. If not then using some oil you can determine if it is the rings or valves. Good luck...

 

[Kpc01]

OK, if pressure test is good will that eliminate the valves and rings? If not how does some oil tell me I have a valve or ring problem?

 

[Redtruck-VA]

OK, if pressure test is good will that eliminate the valves and rings? If not how does some oil tell me I have a valve or ring problem?

When you have identified a weak cylinder, you can squirt some oil into the cylinder and the oil will help seal the rings. If the pressure comes up then the rings are leaking. If the pressure is the same as it was, then it is the valves leaking.