Joined
·
2 Posts
Hello, all....Internet is cool sometimes....
I am A Subaru - Polaris Mechanic..... I own a 90 and 91 3/4 ton 4x4 Suburban...
My Brother owns a 87 1/2 ton 4x4 Suburban....
His is having the issue....
on Start up it lopes at idle real hard then after 10-15 lopes/cycles in cleans up and runs smooth and proper...but idle is high around 12-1500 rpm...It does this every time you start it cold or hot.....
He has replaced throttle body, and all intake sensors trying to get this issue resolved....O2 sensor as well....we pulled the egr unit today to verify it was not plugged or stuck partially open..it is in good shape, and vacuum is good....
ECM trouble lite is giving a trouble code 33 ( low vacuum to map sensor )
I am at a loss at this point as to what is going on...?
I am hoping one of you guys may have had this issue, and can point me down the right road....?
Motor was rebuilt about 45 k ago.....truck has a 700R4 trans, and was getting 17.2-17.9 miles regularly on hwy trips...now it is down around 11-12mpg...?
Thanks, for any info, John in Oregon.
I am A Subaru - Polaris Mechanic..... I own a 90 and 91 3/4 ton 4x4 Suburban...
My Brother owns a 87 1/2 ton 4x4 Suburban....
His is having the issue....
on Start up it lopes at idle real hard then after 10-15 lopes/cycles in cleans up and runs smooth and proper...but idle is high around 12-1500 rpm...It does this every time you start it cold or hot.....
He has replaced throttle body, and all intake sensors trying to get this issue resolved....O2 sensor as well....we pulled the egr unit today to verify it was not plugged or stuck partially open..it is in good shape, and vacuum is good....
ECM trouble lite is giving a trouble code 33 ( low vacuum to map sensor )
I am at a loss at this point as to what is going on...?
I am hoping one of you guys may have had this issue, and can point me down the right road....?
Motor was rebuilt about 45 k ago.....truck has a 700R4 trans, and was getting 17.2-17.9 miles regularly on hwy trips...now it is down around 11-12mpg...?
Thanks, for any info, John in Oregon.