Engine shudder under acceleration when cold

Tiny
ALHARJ
  • MEMBER
  • 2002 GMC SAVANA
  • 8.1L
  • V8
  • 2WD
  • AUTOMATIC
  • 161,000 MILES
Engine starts and idles just fine, shift into gear and accelerates, it sounds like misfire is occurring, no code set. Finally set a code P0337 - camshaft position. Once engine temperature reaches normal 180 degrees it is gone and engine runs perfectly.
Tuesday, March 6th, 2018 AT 5:05 PM

6 Replies

Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
Good morning,

It could be carbon build up on the intake valves that would cause misfire when cold and runs fine when warm. Top engine cleaning will help break up that carbon on the face of the intake valves.

Did the camshaft sensor replacement resolve the check engine light? That is a common failed sensor due to its location.

Another possibility is the transmission causing the shutter.

What transmission? The 8.1 usually uses the Allison Transmission.

Roy
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Wednesday, March 7th, 2018 AT 3:52 AM
Tiny
ALHARJ
  • MEMBER
  • 9 POSTS
Pulled the camshaft position sensor (#12575172) today, will order new part and replace. Transmission is 4L80E.
Thanks.
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Wednesday, March 7th, 2018 AT 4:14 PM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
Okay, replace that and see.

As far as the shutter, the torque converter clutch can cause a shutter. The clutches inside are common for this issue. There is an additive at a parts store for torque converter shutter. You just add it to the fluid and drive it. It takes about ten miles to work in. This will tell you if that is the case. If the shutter stops then the torque converter is the issue. It will have to be replaced if that is the case.

Roy
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Wednesday, March 7th, 2018 AT 4:21 PM
Tiny
ALHARJ
  • MEMBER
  • 9 POSTS
Replaced camshaft position sensor, cleared code, everything is perfect - NO shudder on acceleration on 'cold' engine! Thanks, Al
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Tuesday, March 13th, 2018 AT 3:35 PM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
So the new sensor was no good?

Roy
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Tuesday, March 13th, 2018 AT 3:36 PM
Tiny
ALHARJ
  • MEMBER
  • 9 POSTS
I was letting you know your suggestion worked by installing NEW sensor. Thanks No more problems or codes.
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Wednesday, March 14th, 2018 AT 2:40 PM

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