I AM HAVING ROUGH IDEL PROBLEMS THE TRUCK RUNS ROUGH AND IDELS IRREDICIALY

  • Tiny
  • david sappington
  • 1996 Chevrolet Blazer
  • 156,701 miles

The issue is that I replaced the fuel filter, mass air flow sensor, throtel pos sensor, and vac lines.
i put a new rotor bug and cap on the distrubitor and placed new wires and plugs in it 5r months ago, but I forgot to gap them!
any way I need to figure out how to fix this
my psi gauge for my oil is also acting weird it builds up then drops constantly around as high as 80 psi to below 40 psi at idel and I have noticed that in the exaust if you place your hand near the tip it pulsates
as if to be mis firing but my check engine light is not indicting any of this about 3 months ago I had a lean read out but the shop cleared it and it has not read any simulair code since but nothing was replaced at that time.

frustrated in mo please help

Monday, April 2nd, 2012 AT 2:58 PM

10 Answers

  • Tiny
  • JDL
  • Expert
  • 16,227 posts

Do you have the spider fuel system? It's noted for problems. Does it run ok off idle? Maybe a vacuum leak?

Was this
answer
helpful?
Yes
No
Monday, April 2nd, 2012 AT 3:18 PM
  • Tiny
  • djcl
  • Expert
  • 786 posts

Pull wires off the cap one by one checking for spark and to see which one has little to no affect on the idle. Let's start there.

Was this
answer
helpful?
Yes
No
Monday, April 2nd, 2012 AT 3:19 PM
  • Tiny
  • david sappington
  • Member

Yes it is spider injected and 4 months ago they said it could be bad how do I test this

Was this
answer
helpful?
Yes
No
Monday, April 2nd, 2012 AT 3:25 PM
  • Tiny
  • JDL
  • Expert
  • 16,227 posts

I'd use a gage and check fuel pressure, first. Does it run ok off idle? The other person has a good idea, do a cylinder balance test.

Was this
answer
helpful?
Yes
No
Monday, April 2nd, 2012 AT 3:55 PM
  • Tiny
  • david sappington
  • Member

Ok thanks

Was this
answer
helpful?
Yes
No
Monday, April 2nd, 2012 AT 3:57 PM
  • Tiny
  • JDL
  • Expert
  • 16,227 posts

Let us know what you find.

Was this
answer
helpful?
Yes
No
Monday, April 2nd, 2012 AT 3:58 PM
  • Tiny
  • david sappington
  • Member

I found multiple miss firing plugs on my truck I put new ones on it this morning and since then my motor is running a lot smoother I hit the gas under load and it takes off faster than ever, It still has a small miss in it I am leaning on the distubitior being one or two teeth off from cylinder ones up stroke but all and all it definitly has improved a lot.
I also ran I code check on it last night and I think I may have a bad o/2 sensor on bank one sensor 1 it has no activity so that could explain the miss and fuel issue.
Any way thanks for your help and i'll let you know how things turn out in the near future when I get these other problems fixed, fingers crossed.
So far it seems to be going in the right direction.

Thanks again david
any questions on a miss firing engine e mail me at
davidjanforever@yahoo. Com I have a repair manual for the 96 pos truck that helped figure out what was causing it to miss fire the truck calls for ac delco 12's I put ac 14's in mine and it smoothed out complety through out all shifts and ideling

Was this
answer
helpful?
Yes
No
Tuesday, April 3rd, 2012 AT 3:32 PM
  • Tiny
  • JDL
  • Expert
  • 16,227 posts

Glad you got it going your way.

Was this
answer
helpful?
Yes
No
Tuesday, April 3rd, 2012 AT 3:39 PM
  • Tiny
  • david sappington
  • Member

Bad news today while driving it started acting up again even with the new plugs, im wondering if the coil is bad it has a really white glazed apparence on the front by the magnet on the right side but I dont see any arking on it but when the engine is cold it seems to run ok but after running it a while the symptoms seem to return. Im not sure what to do from here?

P.O again : ( david
please help

Was this
answer
helpful?
Yes
No
Wednesday, April 4th, 2012 AT 4:39 AM
  • Tiny
  • JDL
  • Expert
  • 16,227 posts

Any applicable trouble codes? At the least you need an obd2 code reader to check codes. Some of the national brand autostores used to check codes for free.

Was this
answer
helpful?
Yes
No
Saturday, September 15th, 2012 AT 6:32 PM

Please login or register to post a reply.

Similar Questions