Misfire P0303 - Need some advice

[ChadinSLO]

2008 Yukon. 214,000 miles. P0303 code. Mechanic swapped #3 with #5 plug and #3 wire with #7 and #3 coil with #1. They then performed compression and leak down test. Cyclinder #3 = 100psi. Cylinder #1 = 180psi. Further leak down test on #3 and found 82% leakage. Air escaping through intake and exhaust. Nothing leaking into engine according to mechanic. Mechanic recommending full engine replacement.

Settled up with mechanic ($300) and drove home and then drove another 20 miles or so. Yukon is running fine now. No engine light. I suspect that is just temporary or not?

This mechanic has been great to us over the years. Throwing this out to the community here to see if anyone has other suggestions besides full engine replacement.

 

[j91z28d1]

I'm of no real help here. Just curious if he quoted you a price for the new engine?


I'm guessing if you have a mechanic, you're not really pulling heads and having them fixed yourself, and asking a mechanic to do something he doesn't really want to do, like pulling heads, send to a shop for a refresh, install a afm/dod delete kit (if you have it. I can never keep track of what engine came with what haha) isn't always the best idea


good luck.

 

[ChadinSLO]

I'm of no real help here. Just curious if he quoted you a price for the new engine?


I'm guessing if you have a mechanic, you're not really pulling heads and having them fixed yourself, and asking a mechanic to do something he doesn't really want to do, like pulling heads, send to a shop for a refresh, install a afm/dod delete kit (if you have it. I can never keep track of what engine came with what haha) isn't always the best idea


good luck.

He gave a $10-12K range over the phone. Mentioned a couple of different options he had access to. The real bummer is that we just bought this vehicle from a private owner. No reason to suspect he knew of this issue ...thinking the best here. We did have the vehicle inspected prior to purchase from a mechanic closer to where we bought the vehicle.

 

[strutaeng]

That's a tough question because we need to know how much you are willing to spend and the condition of the vehicle.

Removing "only" that one head and getting it remachined is not an option? I say "only" cause that's still a lot of labor, and maybe your mechanic doesn't want to do it or maybe he thinks it's not worth it? IDK

Another engine from the wrecking yard is another option. Most likely cheaper to just swap, but can be a hit/miss depending on what you get.

Buying a new, remanufactured engine is another option. I think they may be around $5k to $7k currently? Plus labor.

$10-12k to rebuild that one sounds kinda high. Has he done complete overhaul engines? Most mechanics are more like "remove and replace" vs overhaul because it requires different shop space and use. But I'm there's some that do anything.

 

[solli5pack]

Your mechanic is probably recommending an engine replacement just to cover his back with any future issues that could pop up on a 200,000 mile motor. The very least you could do is pull the head and have the valve seals repaired and maybe you'll be good for awhile...

 

[ChadinSLO]

That's a tough question because we need to know how much you are willing to spend and the condition of the vehicle.

Removing "only" that one head and getting it remachined is not an option? I say "only" cause that's still a lot of labor, and maybe your mechanic doesn't want to do it or maybe he thinks it's not worth it? IDK

Another engine from the wrecking yard is another option. Most likely cheaper to just swap, but can be a hit/miss depending on what you get.

Buying a new, remanufactured engine is another option. I think they may be around $5k to $7k currently? Plus labor.

$10-12k to rebuild that one sounds kinda high. Has he done complete overhaul engines? Most mechanics are more like "remove and replace" vs overhaul because it requires different shop space and use. But I'm there's some that do anything.

Thanks for the reply. $10-12K was for a new engine. He mentioned he had a couple of different engine options. That included his labor to put the new engine in. If I want to pursue, he would get a detailed quote.

Posting here to see if there are other options I should pursue based on the details I provided above. Not interested in putting that much $$$ into this vehicle for a new engine. Trying to get a couple of more years out of it.

 

[Fless]

Seems like a borescope might show if one of the valves is cracked or isn't seating properly. The issue with yours sounds similar. Ivan at PHAD recently diagnosed a Jeep with a similar problem, and goes through some of the diag procedures. Take a look at this video; for the borescope test jump ahead to the 11:00 mark.

 

[strutaeng]

Thanks for the reply. $10-12K was for a new engine. He mentioned he had a couple of different engine options. That included his labor to put the new engine in. If I want to pursue, he would get a detailed quote.

Posting here to see if there are other options I should pursue based on the details I provided above. Not interested in putting that much $$$ into this vehicle for a new engine. Trying to get a couple of more years out of it.

Understood.

Check out the video that @Fless just posted

I was going to ask if they performed compression and leak-down on the other cylinders? If everything else checked okay, I personally wouldn't have an issue just reworking that one head. I understand why the mechanic may not want to do just the head, but he also needs to understand your situation. If that means going to another shop for that work, then so be it.

I got a set of heads remachined recently and it was $350 for the pair. Gasket set is another $400 maybe. Labor, I can see it being high for a shop hourly rate. 8-12 hours? Can't be more than maybe $3,000. 1/3 of the other quote.

 

[ChadinSLO]

Understood.

Check out the video that @Fless just posted

I was going to ask if they performed compression and leak-down on the other cylinders? If everything else checked okay, I personally wouldn't have an issue just reworking that one head. I understand why the mechanic may not want to do just the head, but he also needs to understand your situation. If that means going to another shop for that work, then so be it.

I got a set of heads remachined recently and it was $350 for the pair. Gasket set is another $400 maybe. Labor, I can see it being high for a shop hourly rate. 8-12 hours? Can't be more than maybe $3,000. 1/3 of the other quote.

Thank you @strutaeng and @Fless. Video was helpful. I watched the next one as well. Learned a lot. Going to talk to the mechanic and also connect with another shop. Your insights have been great. I'll report back the end of the story as it unfolds.

 

[j91z28d1]

these threads are hard to read. Just know you're not alone. they pop up quite often. it's hard to own high mileage vehicles without being in a position to do some DIY work. repair shops have gotten so expensive. I remember when a used 5.3 at a junk yard was a grand. there was a recent guy in your same situation, just got the truck, did all the inspections you're supposed to and it had a tapping lifter right after getting it. sounded rough on him and his family as an unexpected 10k bill is for anyone after just buying a new vehicle.

if these have afm, did you happen to notice a tapping sound while it was missing? that went away when it cleared up?

the other option I saw in another thread is to buy a extended warranty or whatever they are called while it's running OK? maybe it would help if they cover it.