Automotive Forums .com - the leading automotive community online! Automotive Forums .com - the leading automotive community online!
Automotive Forums .com - the leading automotive community online! 
-
Latest | 0 Rplys
Go Back   Automotive Forums .com Car Chat > GMC > Yukon
Reply Show Printable Version Show Printable Version | Email this Page Email this Page | Subscription Subscribe to this Thread
 
Thread Tools Search this Thread
Old 04-29-2017, 12:31 AM   #1
tonye456
AF Newbie
 
Join Date: Mar 2017
Location: Monterey, California
Posts: 4
Thanks: 0
Thanked 0 Times in 0 Posts
Question 1999 Yukon rough idle

Hey everyone. Well I'm working on a 1999 Yukon with a 5.7 V8. The truck runs great on the city and highway but runs rough at idle and takes a few cranks to start the engine... OBD Codes are P0300 Random Misfire, P0172 System too rich bank 1.
So far we have replaced the spark plugs, ignition coil, cleaned out the throttle body and MAF sensor, ran a few bottles of injector cleaner and checked all the hoses but we can't seem to find the culprit... Anyone have any experience with this issue? I was thinking of checking the O2 sensors as I did get a P0134 O2 Sensor Circuit No Activity Detected but after a code reset we have not been able to get the code to come back Thanks.
tonye456 is offline   Reply With Quote
Old 05-01-2017, 01:39 PM   #2
StumpedGMowner1
AF Newbie
 
Join Date: Mar 2017
Location: Waupaca, Wisconsin
Posts: 37
Thanks: 0
Thanked 6 Times in 6 Posts
Re: 1999 Yukon rough idle

Have you replaced plug wires?
StumpedGMowner1 is offline   Reply With Quote
Old 05-01-2017, 01:48 PM   #3
StumpedGMowner1
AF Newbie
 
Join Date: Mar 2017
Location: Waupaca, Wisconsin
Posts: 37
Thanks: 0
Thanked 6 Times in 6 Posts
Re: 1999 Yukon rough idle

This wont be vacuum leak related at all. So you can rule that out. Even a leaking intake gasket will throw lean codes not rich. Without viewing any live data off the pcm all i can do is give you ideas. Distributor cap and rotor worn, plug wires worn and leaking, bad fuel pressure regulator in spider leaking fuel into vacuum line, stuck open or partially clogged injector. O2S11 can cause this but in my experience its almost never the culprit. I would start with finishing the tune up with new wires and cap n rotor since you already started the tune up anyway and your getting an accompanying misfire code.
StumpedGMowner1 is offline   Reply With Quote
 
Reply

POST REPLY TO THIS THREAD


Bookmarks
Go Back   Automotive Forums .com Car Chat > GMC > Yukon

Thread Tools Search this Thread
Search this Thread:

Advanced Search

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



All times are GMT -5. The time now is 03:42 AM.

Community Participation Guidelines | How to use your User Control Panel

Powered by: vBulletin | Copyright Jelsoft Enterprises Ltd.
 
 
no new posts