The 1947 - Present Chevrolet & GMC Truck Message Board Network







Register or Log In To remove these advertisements.

Go Back   The 1947 - Present Chevrolet & GMC Truck Message Board Network > 47 - Current classic GM Trucks > The 1988 - 1998 Chevy & GMC Pickups Message Board

Web 67-72chevytrucks.com


Reply
 
Thread Tools Display Modes
Old 03-23-2017, 06:57 PM   #1
cam.man67
Registered User
 
cam.man67's Avatar
 
Join Date: Jun 2010
Location: Jefferson, MD
Posts: 2,339
'96 suddenly running really rough

My truck has been running great til today. In the past 2 months I replaced the timing chain, rotor, cap, TPS, so all that's new. Now, today, I'm experiencing a miss at idle (random), lots of sputtering and backfiring at low throttle, and a loss of piwer when accelerating. Any suggestions as to where to start looking? Somebody suggested to me the MAF/MAP sensor (I forget which this has), but I don't know for sure.
__________________
'68 Dodge Dart 270, 225, 904, 2.76--"Lucy"
1996 Gmc 1500 Z71, 350, 4l60e, 3.73s
1995 Jeep Wrangler Rio Grande 2.5, AX5, 4.10s
1989 Toyota Pickup 22re, auto, 3.73
cam.man67 is offline   Reply With Quote
Old 03-23-2017, 08:56 PM   #2
sntrym95
Registered User
 
sntrym95's Avatar
 
Join Date: Jan 2006
Location: Cleveland, Oh
Posts: 527
Re: '96 suddenly running really rough

Kinda sounds like fuel pump. Check your plug wires first, make sure there's no corrosion. Then check your fuel pressure.
__________________
Mike

Toy list:
1995 C1500 Ext. Cab 5.7
1995 GMC Yukon 4dr 2wd 5.7 Vortec conversion, AAM TracRite
1994 Genesis 2001 Bowrider 4.3L Merc Alpha One Gen 2
sntrym95 is offline   Reply With Quote
Old 03-24-2017, 03:33 PM   #3
1952ssr
Registered User
 
1952ssr's Avatar
 
Join Date: Nov 2009
Location: Gainesville Georgia
Posts: 403
Re: '96 suddenly running really rough

My '96 did the same last Friday went from running fine to crap in the stopping at a stop sign. Yours throwing a code? I've changed wires, plugs, gutted cat, tried new coil, crankshaft sensor and will replace injector spider tomorrow. Cap and rotor are less than a year old and fuel pump still sounds strong and was changed about 3 years ago. Mine is giving a P0300 code.
1952ssr is offline   Reply With Quote
Old 03-28-2017, 03:48 PM   #4
cam.man67
Registered User
 
cam.man67's Avatar
 
Join Date: Jun 2010
Location: Jefferson, MD
Posts: 2,339
Re: '96 suddenly running really rough

Go figure, when I drive it down to the shop to get the codes read, it runs like a top.

So, it's running fine now, but had past codes (all from the other day) for:
-faulty right rear o2 sensor heater
-right side converter efficiency (an on and off thing for a year or so)
-faulty crankshaft pos. Sensor
-CPS and cam correlation?
-random misfire (duh)


So I'm going to get a crank sensor, fuel filter (because it's probably time), right side o2sensors, and see what happens. May wind up gutting the cat while I'm at it.
__________________
'68 Dodge Dart 270, 225, 904, 2.76--"Lucy"
1996 Gmc 1500 Z71, 350, 4l60e, 3.73s
1995 Jeep Wrangler Rio Grande 2.5, AX5, 4.10s
1989 Toyota Pickup 22re, auto, 3.73
cam.man67 is offline   Reply With Quote
Old 04-04-2017, 10:27 AM   #5
cam.man67
Registered User
 
cam.man67's Avatar
 
Join Date: Jun 2010
Location: Jefferson, MD
Posts: 2,339
Re: '96 suddenly running really rough

So it's been running fine til this morning, then back to crap. This time I shut it off shortly after it started. Upon restart it ran fine, though I immediately drove it to the shop.

Only code this time is p1345, cam/crank correlation. Could this be caused by a bad crank pos. Sensor? I'm thinking that the other codes might have been caused by the truck running rough for the 45 miles or so it took me to get home.
__________________
'68 Dodge Dart 270, 225, 904, 2.76--"Lucy"
1996 Gmc 1500 Z71, 350, 4l60e, 3.73s
1995 Jeep Wrangler Rio Grande 2.5, AX5, 4.10s
1989 Toyota Pickup 22re, auto, 3.73
cam.man67 is offline   Reply With Quote
Old 04-05-2017, 08:07 AM   #6
Damien
Living the Dream
 
Damien's Avatar
 
Join Date: Mar 2007
Location: Farmington, MN
Posts: 893
Re: '96 suddenly running really rough

The cam position sensor is in the distributor. I'm not sure if it would cause the code or not, but you might want to pull the distributor and check the gear for wear. I wonder if wear on the dist. gear is throwing off the cam/crank timing. Make sure you mark the position of the dist and rotor when you pull it. The vortec engines are a pain to get the timing reset of your off.
__________________
'83 swb 2wd
'74 K5 Blazer
'02 T/A 6 Spd.
'63 Riviera 401
Damien is offline   Reply With Quote
Old 04-06-2017, 06:34 AM   #7
speedygonzales
Registered User
 
speedygonzales's Avatar
 
Join Date: Jan 2006
Location: Smithfield, VA
Posts: 1,244
Re: '96 suddenly running really rough

ICM

Don't forget thermal compound NOT dielectric grease.
__________________
99 Z71 (98 body style)
Pride and joy
speedygonzales is offline   Reply With Quote
Old 04-09-2017, 04:11 AM   #8
cam.man67
Registered User
 
cam.man67's Avatar
 
Join Date: Jun 2010
Location: Jefferson, MD
Posts: 2,339
Re: '96 suddenly running really rough

Well dang if I didn't find the problem! The distributor hold-down bolt had backed itself out just slightly! It was allowing the dizzy to move about 15 degrees either direction, and I'm thinking that as I drove, the motor vibrated enough to turn it ever so slightly. So now I've got it back in place and tightened down...truck appears to be fine now. I will have to rent/borrow a code reader to get the dizzy exactly to where I need it, but I've got it within a couple degrees so that it's running fine now.
__________________
'68 Dodge Dart 270, 225, 904, 2.76--"Lucy"
1996 Gmc 1500 Z71, 350, 4l60e, 3.73s
1995 Jeep Wrangler Rio Grande 2.5, AX5, 4.10s
1989 Toyota Pickup 22re, auto, 3.73
cam.man67 is offline   Reply With Quote
Old 04-09-2017, 11:51 PM   #9
Damien
Living the Dream
 
Damien's Avatar
 
Join Date: Mar 2007
Location: Farmington, MN
Posts: 893
Re: '96 suddenly running really rough

Glad to hear you found the problem. Stuff like this is the worst to track down.
__________________
'83 swb 2wd
'74 K5 Blazer
'02 T/A 6 Spd.
'63 Riviera 401
Damien is offline   Reply With Quote
Old 04-14-2017, 11:45 AM   #10
1952ssr
Registered User
 
1952ssr's Avatar
 
Join Date: Nov 2009
Location: Gainesville Georgia
Posts: 403
Re: '96 suddenly running really rough

Mine was the cap and rotor all along. Runs pretty good now just don't think it likes the cat being gutted. Trying to decide what to do about that.
1952ssr is offline   Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes

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 -4. The time now is 07:07 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Copyright 1997-2013 67-72chevytrucks.com