Ok
well changed that vacuum line to the tranny no change, guess I'll try the intake manifold gaskets next and take a look at the motor while the intake is off after that I'm done and gonna just live with it till something other than PO301 comes up. I Was trying to get this solved because I'm due for emissions testing. Have a good weekend!!
GS

 

I'm reading through my Chevy service manual and came across something interesting
Was wondering what you think.
In reading the description of a DTC PO301 I came across this quote
"The VCM also utilizes input from the ABS Wheel speed sensor in order to determine (rough Road conditions)which would cause crankshaft accel and decel If a rough road condition exists
the diagnostic will not run" The reason I'm asking your opinion is because my ABS light has been on for about as long as this rough idle problem The codes stored are C0065 "pump relay circuit open" and C0068 "Pump Motor stalled or Pump Circuit shorted". I also remember another code being stored a while ago refering to the left front wheel speed sensor but can not find it stored in memory The Abs light comes on as soon as I hit 3 MPH. If the VCM utlilizes info from the abs system and my ABS system is not working correctly could that trigger the PO301 and cause my Rough idle It's a shot in the dark but just wondering what you think
Thanks
GS

 

If your ABS light is on, the system should be disabled and any input it has to any other system should be ignored. "Should"....

 

Ok thanks for the input on that,Guess the last thing i'll try is intake manifold gaskets. I tighten the bolts down Sat night and there seemed to be slight improvement
I can hear an air sound coming from the front of intake as well but can't narrow it down
I was also reading up a little on the fuel trims which should be close to 0% and monitored them the last 2 days back and forth to work. Long term depending on engine speeds are anywhere from 0%to +4%
Short term go from 0% up to +3to +5 % down to -4 depending on accel or decel. At a steady 65 mph they are both around 0% I know they fluctuate depending on engine speeds but possible an air leak could be affecting them.

 

If you had an air leak, the fuel trims should be accounting for it meaning higher positive trims.

 

Those were the averages at traveling speeds. at idle they are in the pluses gonna give it a shot anyway. I'm learning a lot along the way anyway hopefully I'll get it one of these tries Thanks again for responding I really appreciate your input. Hopefully I'm helping people along the way. Will update probably after Tuesday this week

GS

 

changed intake manifold gaskets today, no luck still a PO301 and rough idle
I have to put a new muffler and tail pipe on it to eliminate my exhaust leaks then gonna do
a cylinder leak down test, then make sure my fire insurance is up to date LOL!
GS










o

 

Going to change Motor Mounts(they look worn out) Exhaust manifold gaskets, flange gasket, and tailpipe to quiet up my exhaust and see if it calms it down seems to be a slight leak in the manifold gasket near cylinder #1 probably wont solve my PO301 but needs to be done waiting for my cylinder leak down tester from Harbor Freight

 

Let us know how that goes.

 

In preparation for next weeks exhaust work I decided to check my driver side Exhaust manifold bolts and see if they would loosen, Guess what they are already loose especially the ones at cylinder #1. almost a full turn to tighten it up unfortunately The front bolt is blocked by the power steering pump bracket. so tightend the rest of them up all took 1/4 to 1/2 turn to snug up and the mis is almost gone with no SES light in 2 days