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garre1tt
08-15-2011, 16:38
My 97 suburban just started a strange surging at 1800 RPM or 60 MPH. Faster or slower it is fine. It happens again at 2300 RPM and or about 77 MPH and it will not allow any higher RPMs. It feels like it is hitting a governor. Checked out the fuel system and have good pressure, 7-8 psi consistent. No codes present.
This happened in the middle of cross country trip. Loss of about 6 MPG. Any thoughts?
Burning Oil
08-17-2011, 08:06
Fuel pressure checked under way or parked? where are you taping to get your reading?
Burning Oil
08-17-2011, 08:08
Also you might consider 195 Tstats. When I went from 180 I got 3-4 MPG better.
garre1tt
08-17-2011, 10:57
The fuel pressure is from the lift pump. The milage decrease is from the first half of the trip to the return. first leg burb ran great from WA State to Florida getting 18 to 20 MPG.
Trip home best is 16 MPG.
Burning Oil
08-17-2011, 11:18
The fuel pressure is from the lift pump. The milage decrease is from the first half of the trip to the return. first leg burb ran great from WA State to Florida getting 18 to 20 MPG.
Trip home best is 16 MPG.

If your getting your reading right at the pump then you could have a restriction in the line to FFM, the filter needs replaced, the last ditch screen inside the FFM or the screen inside the IP inlet fitting could all need atention.
Also the Tank sock and line from tank to LP should be cleared.
These are the items I would check first as they are cheap and common issues.
garre1tt
12-08-2011, 01:02
Several months now and the problems just kept getting worse. The stuttering happens at all speeds and RPMs. Think I got it narrowed down to the IP going bad.