2003 GMC Yukon XL 1500

Ladylanum

New member
I am wondering if anybody has any suggestions for me. Here is the story...

(a little back ground info, I don't know if this is important or not) In May of 2012, we were going on a little road trip. The car started hesitating quite a bit while on the interstate (going 76 mph). The check engine light came on, flashing, staying on, flashing again. It got to the point where when we came to a hill, the Yukon didn't seem like it was going to make it. So, we took a little side trip to the zoo to let ole Yukey settle down. About an hour later I started it up and it seemed to run fine but decided to head home (we were 45 minutes out) instead of continuing on our way. About 15 minutes into the drive, the hesitation started up and got so bad that we were struggling to do 25 mph. So, every 15 minutes or so I would pull over for 10 minutes and continue on down the road. It took along time to get home.

Went to Firestone, they said mass air flow sensor, I said change it. Everything seemed ok, but I did notice quite a bit of hesitation anytime it was idling, especially if the ac was on.

The check engine light finally came back on in October of 2012. This time, blinking and then staying on and then blinking. This was constant. There was quite a bit of hesitating and the Yukon was running pretty rough by February of 2013. So, I took it back to Firestone.

They said intake manifold gasket. I said change it.

Engine light continued to come on and then blink and then stay on and then blink. The Yukon continued to run rough, hesitating. So, I took it back to Firestone.

They said crank position sensor. I said are you SURE?

I went with the technician while he drove and talked with him about my doubts concerning all of these going ons. He assured me this would take care of everything. Later on in the day, check engine light comes on, stays on, flashes, and I think I may have even heard nana nana boo boo.... So, I took it back to Firestone. Random Misfiring. A phrase I would hear over and over for months to come.

They said, with a solemn and grave disposition, it is one of the catalytic converters (I believe it was the front left). I said ok, let me talk with some people. He gave me a quote with a discount, total being $782. You know you have to replace both because it is all one piece, naturally.

Went to Advance Auto and said, my check engine light is on, can you help? So, he ran it and gave me a looooong list of codes, all pointing basically to the cat converter (random misfiring). Then, my husband says, let's take it to my mechanic, he'll cut both off and weld on aftermarket ones for $259. Oh, so many doubts and questions. But, I am a humble, submissive wife. I said do it.

Dropped the car off, was told it would be ready in two hours. Seven hours later I hop in, drive off and watch as the light happily blinked away. Took it back to the mechanic, he said, random misfiring, it's the spark plugs, Firestone put in the wrong ones, they could have ruined the coils. I'm like, uh huh (I don't know who to believe at this point). So I said change them. He said that will take care of. Lord knows I don't want to question him with, could it be the aftermarket cats??

So I hop in, drive off and once again enjoyed the blinking, now almost memorizing light show that I have come to look for when I start down the road. I call up the mechanic and he says, oh it's got to be the fuel filter. At this point, let me just say this is starting to become entertainment to me. I mean, how many mechanics does it take to stop the blinking?? He proceeds to change the fuel filter. Shows me the filter and says look at all that gunk. Honestly, I saw no gunk, but what do I know. He said that will take care of it. You won't have any problems now. The check engine welcomes me to the Yukon as I head home. I call the dealership and tell them the story, could it be the aftermarket cats? Why, yes.

I called the mechanic back and he said, it has to be the ignition coils. It was Firestone's fault for putting in those bad spark plugs. I call up my ex, Firestone, and explain to them what has happened. This seemed to only strengthen my relationship with the manager somehow. So, I take it to Firestone, they say, the codes are saying random misfiring, coil 5. I said CHANGE IT! Now, at this point, Firestone realizes hey, this light MIGHT just come back on. So, they take it out and sure enough it does. They run the diag again, random misfiring, spark plugs 1 & 5, but wait, the other mechanic just changed those to the best of the best. This doesn't make any sense! So, just for fun, he changes the two plugs and the diag says RANDOM MISFIRING, plug 3. He says, something isn't right here. I just smile.

So, I decide I need a little vacation from all this fun.

In October I take ole Yukon to her second home, Firestone, where I handed them an arm and a leg in return for the cat converters. The engine light did not come back on until the next day. Meanwhile, during all of this, the Yukon is running rough, hesitating while idling, and sometimes the heat would not come on but just blow cold air. I call Firestone.

They do some research and while this is going on the other mechanic tells my husband it is probably an O2 sensor. Firestone says is the O2 sensor, front right. They change both of them. I did not pay for this. Light came back on, random misfiring. Took it back, they changed the other sensors, I did not pay for this, light came back on, random misfiring, I took it back. They brought it to the dealership and had them run a diag on it, the dealership says random misfiring, it's the fuel pump, Firestone takes it back and changes the pump. The light comes back on and the fuel gage is now NOT WORKING. Is this progress in disguise? I take it back, they change the pump again because the dealership said it was the pump so it has to be the pump! The lights comes back on, the fuel gage is still not working correctly (the gauge goes up and down as it pleases, when I fill the tank it won't go to full, more like 3/4).

It is now December of 2013 and the saga continues. I called Firestone and said what now? He said bring it to dealership, they know the story, have them charge me for the diag and tell me what they say. So, Monday the Yukon goes in, again.

Let's recap what has been changed so far:
mass air flow sensor
intake manifold gasket
crank position sensor
spark plugs
fuel filter
cat converters, twice
coil 1
all O2 sensors
fuel pump, twice

The light now seems to only come on at interstate speeds, above 60. It flashes, stops, flashes, stops. If I drive at interstate speeds long enough, it will stay on even if I shut the car off and get back in (like grocery shopping or something) and drive through town. I start the car up in the morning and sometimes it is not on and sometimes it is on, not blinking (it never starts out in the morning blinking). Once, I was driving away from Firestone accelerating to 45 mph, not quickly, just heading down the road, and the car jerked hard into gear and the light came on immediately flashing. Just the other day I went to back out of a parking space and had it in reverse but it acted like it was in neutral. I put it in park and then back to reverse and it was fine. A couple of times I have been driving in town and had it hesitating so bad it almost shut off. I would pump hard on the gas, nothing, I would give it constant gas, nothing. I was like when I has a fuel filter put on wrong once on another car and I had to drive it like it was a clutch (the gas and break) to keep it going.

Anyway, that is my story. Any ideas before I go to the dealership?
 

Smokin' Denali

New member
WOW! Do you have Comprehensive Ins?? Get some matches and lighter fluid....no seriously, it could be bad fuel, loose wire etc. You must go to another Dealer for a 3rd opinion. Some things computers cannot fix. You need an experienced Yukon mechanic...
At least when you're done you can drive it a few more years. I paid about $4K just in sales tax when I bought my 2011!! Feel any better? lol
Best of luck!

SD
 

Ladylanum

New member
Thanks for the reply!

I went to the dealership to drop the Yukon off in the morning. I called around noon to see if they had an update. What he said confused me a little, but did not surprise me to say the least. He said they would have to give the Yukon to one of the mechanics to take home with him to drive for a couple of weeks to assess the situation. He said this was the only way. (is that normal??) I said I am coming to pick up the Yukon and I'll call you back later. After letting my frustration subside and the anger that was trying to well up in me calm down, I came up with an amazing idea. I am going to tape a smiley face over the check engine light and drive it until it breaks down. Meanwhile, I may contact Guinness Book of World Records and let them know that I am driving a vehicle that no one can fix! I only need the vehicle a couple of more years anyway until my daughter, who plays the harp, gets her own vehicle.

It is a curious ordeal; I would love to know what is going on. I may call around to some other mechanics and brief them on the story. Maybe someone will have an epiphany and enlighten us all!
 

Molson02536

New member
Thanks for the reply!

I went to the dealership to drop the Yukon off in the morning. I called around noon to see if they had an update. What he said confused me a little, but did not surprise me to say the least. He said they would have to give the Yukon to one of the mechanics to take home with him to drive for a couple of weeks to assess the situation. He said this was the only way. (is that normal??) I said I am coming to pick up the Yukon and I'll call you back later. After letting my frustration subside and the anger that was trying to well up in me calm down, I came up with an amazing idea. I am going to tape a smiley face over the check engine light and drive it until it breaks down. Meanwhile, I may contact Guinness Book of World Records and let them know that I am driving a vehicle that no one can fix! I only need the vehicle a couple of more years anyway until my daughter, who plays the harp, gets her own vehicle.

It is a curious ordeal; I would love to know what is going on. I may call around to some other mechanics and brief them on the story. Maybe someone will have an epiphany and enlighten us all!
Sorry for the running around the techs have you doing. What exactly are the codes your getting??? Best thing to do is clear the codes and take a new scan of any present and active codes your getting.

My shot in the dark would be a bad knock sensor or bad led wire from your knock sensor. The computer will retard your timing when knock occurs. Without functioning sensors, it will not compensate. This can be damaging over time if there is a pre ignition (misfire) problem.

Knock sensor codes are P0327 bank #1 and P0332 bank #2 but both are located in the valley between the left and right banks under the intake manifold.

The 4.8L, 5.3L and 6.0L engine all had considerable problems with moisture leaking into the knock sensors. GM advises inspecting the sensors and replacing any that show signs of corrosion or moisture damage. A further precaution is to build a dam with silicon sealant to prevent moisture from running into the 2 knock sensor areas.

Good luck and keep us posted and try to get your dtc codes cleared. ;)

Molson02536
 

johnnyidaho14

New member
Sorry for the running around the techs have you doing. What exactly are the codes your getting??? Best thing to do is clear the codes and take a new scan of any present and active codes your getting.

My shot in the dark would be a bad knock sensor or bad led wire from your knock sensor. The computer will retard your timing when knock occurs. Without functioning sensors, it will not compensate. This can be damaging over time if there is a pre ignition (misfire) problem.

Knock sensor codes are P0327 bank #1 and P0332 bank #2 but both are located in the valley between the left and right banks under the intake manifold.

The 4.8L, 5.3L and 6.0L engine all had considerable problems with moisture leaking into the knock sensors. GM advises inspecting the sensors and replacing any that show signs of corrosion or moisture damage. A further precaution is to build a dam with silicon sealant to prevent moisture from running into the 2 knock sensor areas.

Good luck and keep us posted and try to get your dtc codes cleared. ;)

Molson02536
Good day, I have the 0332 code on my 2002 yukon denali xl 6.0 and am going to replace both knock sensors. Would appreciate any and all instructions for the disassembly. Just finished changing out my valve cover gaskets and oil cooler lines plus rear shocks and compressor and feel good about this work as well just need some guidance on the disassembly, thanks
 
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