1997 GMC TRUCK DIES AND WONT START WHEN WARM

  • Tiny
  • 97z71
  • 1997 GMC Truck

Engine Mechanical problem
1997 GMC Truck V8 Four Wheel Drive Automatic

I just put a new 5.7 engine in my truck.
It runs great when cool but as it gets warm will start a slight sputter and die when approaching stop lights, signs, etc.
When it does this it is throwing a check engine light that is never on when it is cool and running good. It will start back but you have to hold it to the floor and it will sound like you pulled off a few plug wires(pop, pop, pop pop) and sometimes will smooth out but not always. When it cools back down it starts and runs fine again.
I have replaced the spider injection, crank position sensor, and plugs.
Can a CONTROL MODULE cause this?
I cant get it anywhere to check the codes for awhile but my father in law owns a salvage yard where getting parts to swap are fairly easy.
Thought there might be a couple " common" causes. Thanks, Rod Hipsher

Friday, May 21st, 2010 AT 9:38 AM

11 Answers

  • Tiny
  • 97z71
  • Member

I just ran the codes with a scanner and get the following

p0339 Camshaft position sensor A circuit intermittent (did not show until it started to run bad and die)
p0341 CPS A circuit range performance (bank 1 or single sensor)

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Friday, May 21st, 2010 AT 6:37 PM
  • Tiny
  • 97z71
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I thought I donated 5 dollars for a guranteed answer?

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Sunday, May 23rd, 2010 AT 3:47 PM
  • Tiny
  • mmprince4000
  • Expert
  • 8,715 posts

Sorry for the delay.

Best approach is to scan CPS in live data mode with scanner, look for erratic output.

If crankshaft sensor has been replaced, then replace the camshaft sensor.

Was previous engine a 5.7?

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Wednesday, May 26th, 2010 AT 8:43 AM
  • Tiny
  • mmprince4000
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  • 8,715 posts

P0341 diagnosis:


http://www.2carpros.com/forum/automotive_pictures/108325_p0341_1.jpg

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Wednesday, May 26th, 2010 AT 9:02 AM
  • Tiny
  • 97z71
  • Member

Yes I replaced Crank and Cam sensors. Previous motor was 5.7 350 same.
It is only happening when warm, runs like a top for about three miles?
It is at a garage now being hooked to a tech II
Thanks

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Wednesday, May 26th, 2010 AT 9:31 AM
  • Tiny
  • mmprince4000
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Just remembered, they will have to program new VIN into PCM, TechII can do that.

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Thursday, May 27th, 2010 AT 8:28 AM
  • Tiny
  • 97z71
  • Member

Well it has been to 2 shops and noone can figure this thing out?
Are you saying that buy entering new vin into scanner. To refash computer?
This thing runs great and if you wipe the code it will not throw it again until it has idled for about 10 minutes then it is like you pulled 4 plug wires off, starts, missin, backfireing through exaust. And throws the check engine light.
Do these computers need flashed for a new(rebuilt) block?

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Monday, June 14th, 2010 AT 7:18 AM
  • Tiny
  • mmprince4000
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PCM must be reflashed with correct VIN. A TechII can do this.

Security system could also be problem.

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Tuesday, June 15th, 2010 AT 9:25 AM
  • Tiny
  • 97z71
  • Member

The vin from engine or from the truck itself?
It has been hooked to a tech2 where they entered the vin under windshield.
This thing has us baffled. Changed all the sensors. And its is still throwing that cps (cam position sensor) code but not until it runs for a while.I can drive it 3 miles and it runs like a top. Checked fuel pressure it is in like the 65 + pound range. Changed computers, changed distributor (runs fine in my 97 suburban).
I am so lost on whats causing this, this truck ran great before removing the engine it just had a bad lower end knock.

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Tuesday, June 15th, 2010 AT 9:43 AM
  • Tiny
  • mmprince4000
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Have the CPS data read in live data mode, if within specs, then PCM, if not then CPS or wiring to it.

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Wednesday, June 16th, 2010 AT 7:13 AM

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