i have a 2003 qc 4x4 with the 5.9 gas, yes it is a 5.9 it was a option for the first part of 03. well i had a misfire code a few months back so i changed my wires, plugs, cap, and rotor. problem went away, then other morning i go to get on the highway and my cel starts to flash and my truck is hesitating bad. about 10 minutes later all was well and no cel. i got smart and got my truck inspected ( here in ny if you have a cel you wont pass) and passed. now today its snowing like hell i go to work hop on the highway and bam its doing it again but this time the light stayed on and is throwing code p0307, last time it was cyl # 2 + 8, now its 7 so what could it be? i only have 57000 miles on it and i know i have the 7/70 but im wondering if it could be a head issue, and if it is, is the head covered by the powertrain warrenty?any ideas please let me know thanks!!!

 

Yes the head is covered.Prety much anything on the engine that came from the factory.I wouldn't worry about it.Let the dealership do what its supposed to do with a product they sell you,SERVICE!.

 

that makes me feel better about the warrenty, but im gonna do the plugs myself i dont go to the dealer except for big stuff, any other ideas about the cel. also if i did bring it to the dealer what do they charge to diagnose these problems

 

When I blew my Passanger side head gasket,which later became a cracked head,they charged me 100 bux just to check the truck.The rest was charged to the warranty.I got a Brand spankin new head and gasket with brand new Exhaust manifolds.Labor + PARTS = only 100 bux they charged me to look at it.

 

A couple of simple things I can think of.

1. You may have water rolling around in your gas tank, you may also have water up in the fuel rails. Get a couple of bottles of RED Bottled dry gas and dump into a full tank.
You also may have injector inlet clogging due to rust particles being deposited in the injector inlet---it is caused by rusting occuring in the fuel rails. The fix for this is to pull the rails and injectors and clean them out--happened to a guy at work with the same year truck as yours.

2 The injector on that cylinder is getting crudded up and not spraying right. Get a couple of cans of SEA Foam and dump into a full tank of gas. You may also want to do a top end clean using Sea Foam slowly poured into the vacuum hose to the brake booster while someone helps to keep the engine running. Make sure the engine is up to FULL operating temp. This may help dislodge any crud built up on the injector pintles.

These are my quick fix ideas. The others such as heads being cracked or gaskets blown, are better diagnosed by the Service dept. unless you have the tools and such to try it yourself.