Dies when not given gas?

Tiny
WHOPPEY
  • MEMBER
  • 2006 BUICK RENDEZVOUS
  • 3.5L
  • V6
  • 2WD
  • AUTOMATIC
  • 158,000 MILES
I'm trying to help a friend who recently got screwed over by a very expensive "mechanic". The main problem he's having is the car idles kinda rough and it dies whenever he lets off the gas at red lights, stop signs, etc. I was thinking a dirty idle air control valve or throttle body. I checked for vacuum leaks and everything was good there. Its got newer sparkplugs and wires from previous mechanic.
Friday, August 29th, 2025 AT 1:15 PM

1 Reply

Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 54,852 POSTS
So we need to check the engine compression which will cause this kind of issue. Also, you must make sure the correct spark plugs were installed. Here is a guide to help with the testing

https://www.2carpros.com/articles/how-to-test-engine-compression

These are the spark plugs that need to be installed.

ACDelco 41-101 (Professional Iridium) - this is the OEM plug GM spec’d for that engine.

Gap: 0.040 in (1.0 mm)

Please upload what the spark plugs look like so I can see them to tell what might be happening as well when you get back to us.
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Friday, August 29th, 2025 AT 6:05 PM

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