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95 Blazer rough idle


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Join Date: Jun 2009
Posts: 7

June 9th, 2009, 5:59 PM   #1  
CF Beginner
95 Blazer rough idle

Hey guys,
I'm new to this forum have been trying to solve a rough idle issue for some time here is a list of things that have been done hopefully someone can help me, I've posted on another forum with some help but here is my summary
I replaced my spider injector unit today
, But the new unit did not solve my Po301 problem misfire cylinder #1 symptom is (Rough Idle) Here is a list of all the stuff I have done to try and resolve this issue. If there is something You think I might have missed please let me know.
Components changed
High Voltage ignition switch (distributor) includes new cap & rotor
Coil, Plugs, Wires.
Throttle Position sensor, Idle Air Control sensor, O2 sensors, Egr Valve with screened gasket, Coolant Temp sensor. Checked Voltage at each connector as well all are at recommended voltages
within the last 2 months have replaced the Muffler and Cat Converter
New Muffler, Cat Converter
conducted a compression check on cylinder #1 compared to cylinder #5 both the same
while truck was running i applied pressure in each direction to see if a valve guide was worn but no results,

Components I have not changed
MAP sensor
Ignition control Module. From what I understand this either works or doesn't work found some post one other sites where it could possible cause my symptom
I'm kind of ready to throw in the towel Only thing I haven't done yet is a cylinder leak down test. If you have any suggestions please give them to me
Thanks

 
Join Date: Mar 2009
Posts: 1,659
Michigan

June 9th, 2009, 10:09 PM   #2  
Super Moderator
Have you tried Vacuum lines? What is your fuel pressure? Fuel filter? Try running sea foam through it.

 
Join Date: Jun 2009
Posts: 7

June 10th, 2009, 4:46 AM   #3  
CF Beginner
Ran all new vacuum lines seafoamed it and fue pressure holds at 60lbs not running 57lbs running, was wondering if a tired ICM might be the culprit
No stalling issues infact the truck runs better than ever with all the component replacements i've done except at idle, any other suggestions would be great
Thanks

 
Join Date: Mar 2009
Posts: 1,659
Michigan

June 10th, 2009, 5:44 PM   #4  
Super Moderator
Ignition control module usually just goes out. Try tapping it with a screwdirver well its running and see if it sputters but I would not think that this would be the culprit. Did you try fuel filter? Whats your compression run all around?

 
Join Date: Jun 2009
Posts: 7

June 11th, 2009, 6:33 AM   #5  
CF Beginner
Changed the Fuel filter about a month ago, the fram one I had in it completely
failed inside was like a rattle but will put another one on. I did a compression test on cylinder #1 and #5 for comparison it was just a little over 120lbs

 
Join Date: Mar 2009
Posts: 1,659
Michigan

June 11th, 2009, 4:52 PM   #6  
Super Moderator
Thats pretty low! You Should test all of them!

 
Join Date: Jan 2008
Posts: 1,637
Westminster, Md.

June 11th, 2009, 7:37 PM   #7  
Super Moderator
Ride of the Month
May 2009
When you changed the TPS did you test the voltage and adjust the idle and wide open throttle signal?

 
Join Date: Jun 2009
Posts: 7

June 11th, 2009, 9:57 PM   #8  
CF Beginner
mudmaniac  When you changed the TPS did you test the voltage and adjust the idle and wide open throttle signal?
Yes I had it hooked up to a tech 2 scanner and closed throttle and WOT were within the specified voltages, I'm gonna replace the IAC, MAP, and ICM
and if that does not solve it gonna have to consult the pro's on this one
Spent today looking for vacuum leaks and gasket leakes but no luck!!

 
Join Date: Mar 2009
Posts: 1,659
Michigan

June 12th, 2009, 4:22 PM   #9  
Super Moderator
There is a way to test the mapsensor! Do you have a Haynes manual? Mudmaniac how do adjust TPS? I don't think I did that when I replaced mine?

 
Join Date: Jun 2009
Posts: 7

June 12th, 2009, 8:58 PM   #10  
CF Beginner
i don't think you can adjust a TPS but if you know how to test the Map sensor please let me know I have the 3 GM manuals for my 95 but didn't see anything

 
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