Sign up to remove ads. We'd love to have you amongst our ranks! Just Click here!


gmc forums   gmc forums


Go Back   GMC Forums > GMC Vehicles No Longer In Production > GMC Envoy Forum

Advertisements
cars connected social network






Notices

GMC Envoy Forum Forum for discussions regarding the GMC Envoy


GMC Forum: 2008 Envoy 4.2L PO300, PO352 , PO353
View Poll Results: PO352, PO353
PO300 0 0%
Engine miss 0 0%
Voters: 0. You may not vote on this poll

Reply
 
Thread Tools
  #1  
Old 05-25-2017, 01:37 PM
Swampfox21 Swampfox21 is offline
Junior Member
Drives a
 
Join Date: Jan 2015
Location: Westchester Cty, NY
Posts: 4
Smile 2008 Envoy 4.2L PO300, PO352 , PO353

Started my Envoy after being parked for 4 days in my garage and engine had a severe miss.. 91,000 miles on her. Had been running fine and this is the first engine issue in 3 years.

Pulled down the codes.. PO300, PO352, PO353.. Intermittent miss cyl #2 & #3. So I pulled the plugs and started trouble shooting. Plugs looked good but since I was there A pulled them all and replaced them all with new AC iridium plugs.

Checked for spark from the coils with HEI tester. No spark from #2 & #3.

Have solid 12 volts to the coil wire and a solid ground, Signal line did not show any pulse. (3 wire COP)

Couldn't find a wiring diag. on line so I ended up taking the thing back to the dealer figuring it was either the ECM (new one would need to be programmed)or wiring (Need print).

Problem turned out to be in the wiring harness from the ECM to the coils. The Tech found 6 broken/frayed wires in the harness where the wiring goes down under and behind the ECM. He had to strip back a good amount of the plastic to find the broken wires. He found the broken wires for the coils by following their color codes. Along the way he found 4 additional frayed/broken wires.

The tech did the repairs and sealed and repacked the wires in the plastic shield. Spark had now returned to the cyl #2 & #3. $$ (4) labor Hrs later the Job was done.

Glad to have my Envoy back on the road and running properly.

Steve D.
Reply With Quote

Reply

Tags
po300, po352, po353
Registered members see less ads. Please sign up! We'd love to have you...

Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -5. The time now is 12:38 PM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2018, vBulletin Solutions Inc.
gmcowners.com recognizes that "GMC", it's logos and various model names and numbers are registered trademarks of the General Motors Corporation. These terms are used for identification purposes only. gmcowners.com is not affiliated in any way with the General Motors Corporation, GMC or any other company listed herein. All information on this site is the opinion of its members and not the opinion of the site itself. ©2017 Madison Ross Media Group. All rights reserved. Content published on GMCOwners.com requires permission for reprint.


MADISON ROSS MEDIA GROUP MARKETPLACE
Need products for your GMC Truck? Check out your options at the links below:

Looking for something a little sporty? Believe it or not, Kia may have something for you. The Kia Stinger is a large sport-oriented hatchback sedan in the mold of the Audi A7.