Fix the wiring issue that’s causing your blower fan to act up first. Resistor won’t fix it.
2006 LBZ GMC Sierra Surging/Stutter w/ weird electrical gremlins. PO336 Code Thrown
Having a really sporadic and wild issue with my Duramax as of recently. The truck has 204k with pretty great maintenance.
This issue has been pretty intermittent over the last 2500 miles or so. Below is a video of what is going on, this instance is about the worst it gets but when towing it is violent to say the least. First happened a month ago and while towing about 12k pounds. Happened a few times on the trip but never threw a code. Choked it up to be a fuel line pinching and decided to install a lift pump per recommendations from a shop I chatted with.
The truck basically falls on its face for a 1/4 second. Sometimes one quick one, sometimes 2 or 3 times, and when it's really bad the doors all lock.
3 weeks go by with a lift pump, no issue. Drive 500 miles up to Montana with almost no issues until the last 45 minutes. Exact thing shown in the video. A few minor ones after. Some going fast some stuff 10 mph on a dirt road.
On the way home, it happened about 10-15 times. Runs perfectly fine in between, maybe a bit low on power but I was in a headwind and babying it at this point.
Code thrown is po336 Crankshaft Position Sensor.
My thoughts are leaning towards the wiring issue instead of fuel or the Crankshaft position sensor actually being wrong. Along with this the doors sometimes lock and as of very recently, my blower motor is stuck in one speed and also does not turn off with the truck even with the key out of the ignition.
I already ordered a new blower motor resistor to see if that fixes that issue and will update on that shortly. Today I plan to give it the old ford shakedown test and let the truck idle and shake all my wiring to see if it gets anything to stutter or do weird things. Chase all the wiring especially to the CSP. I will update on that shortly too.
Also, had about 40 miles of range left, was doing this regardless of how much fuel I had so do not pay too much attention to the low fuel. Truck was getting around 17.5-19 mpg the whole trip with 1500 pound slide in camper on.
I have a straight pipe, AFE intake, Edge Juice with Attitude on the 1st tune "Milage". May also try unplugging the Juice as I have heard they can cause some wacky shit.
Any ideas appreciated.
Click to watch.
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This issue has been pretty intermittent over the last 2500 miles or so. Below is a video of what is going on, this instance is about the worst it gets but when towing it is violent to say the least. First happened a month ago and while towing about 12k pounds. Happened a few times on the trip but never threw a code. Choked it up to be a fuel line pinching and decided to install a lift pump per recommendations from a shop I chatted with.
The truck basically falls on its face for a 1/4 second. Sometimes one quick one, sometimes 2 or 3 times, and when it's really bad the doors all lock.
3 weeks go by with a lift pump, no issue. Drive 500 miles up to Montana with almost no issues until the last 45 minutes. Exact thing shown in the video. A few minor ones after. Some going fast some stuff 10 mph on a dirt road.
On the way home, it happened about 10-15 times. Runs perfectly fine in between, maybe a bit low on power but I was in a headwind and babying it at this point.
Code thrown is po336 Crankshaft Position Sensor.
My thoughts are leaning towards the wiring issue instead of fuel or the Crankshaft position sensor actually being wrong. Along with this the doors sometimes lock and as of very recently, my blower motor is stuck in one speed and also does not turn off with the truck even with the key out of the ignition.
I already ordered a new blower motor resistor to see if that fixes that issue and will update on that shortly. Today I plan to give it the old ford shakedown test and let the truck idle and shake all my wiring to see if it gets anything to stutter or do weird things. Chase all the wiring especially to the CSP. I will update on that shortly too.
Also, had about 40 miles of range left, was doing this regardless of how much fuel I had so do not pay too much attention to the low fuel. Truck was getting around 17.5-19 mpg the whole trip with 1500 pound slide in camper on.
I have a straight pipe, AFE intake, Edge Juice with Attitude on the 1st tune "Milage". May also try unplugging the Juice as I have heard they can cause some wacky shit.
Any ideas appreciated.
Click to watch.
1 - 16 of 16 Posts
Electrical issues are the worse. The blower operating when ignition off is a big one, must be a short someplace need to track that down. Also there is a common earth on the frame just under the driver door that tends to get corroded and cause all sorts of weird things.Having a really sporadic and wild issue with my Duramax as of recently. The truck has 204k with pretty great maintenance.
This issue has been pretty intermittent over the last 2500 miles or so. Below is a video of what is going on, this instance is about the worst it gets but when towing it is violent to say the least. First happened a month ago and while towing about 12k pounds. Happened a few times on the trip but never threw a code. Choked it up to be a fuel line pinching and decided to install a lift pump per recommendations from a shop I chatted with.
The truck basically falls on its face for a 1/4 second. Sometimes one quick one, sometimes 2 or 3 times, and when it's really bad the doors all lock.
3 weeks go by with a lift pump, no issue. Drive 500 miles up to Montana with almost no issues until the last 45 minutes. Exact thing shown in the video. A few minor ones after. Some going fast some stuff 10 mph on a dirt road.
On the way home, it happened about 10-15 times. Runs perfectly fine in between, maybe a bit low on power but I was in a headwind and babying it at this point.
Code thrown is po336 Crankshaft Position Sensor.
My thoughts are leaning towards the wiring issue instead of fuel or the Crankshaft position sensor actually being wrong. Along with this the doors sometimes lock and as of very recently, my blower motor is stuck in one speed and also does not turn off with the truck even with the key out of the ignition.
I already ordered a new blower motor resistor to see if that fixes that issue and will update on that shortly. Today I plan to give it the old ford shakedown test and let the truck idle and shake all my wiring to see if it gets anything to stutter or do weird things. Chase all the wiring especially to the CSP. I will update on that shortly too.
Also, had about 40 miles of range left, was doing this regardless of how much fuel I had so do not pay too much attention to the low fuel. Truck was getting around 17.5-19 mpg the whole trip with 1500 pound slide in camper on.
I have a straight pipe, AFE intake, Edge Juice with Attitude on the 1st tune "Milage". May also try unplugging the Juice as I have heard they can cause some wacky shit.
Any ideas appreciated.
Click to watch.
![]()
1 - 16 of 16 Posts
