'87 Suburban TBI Problems

On a recent trip I was cruising along at about 70mph. The check engine light came on and I noticed that there were some minor performance issue. However upon slowing down the engine began to stutter considerably. It know sits in my drive way with several failed attempts at repair. Symptoms are as follows:

1)Revs and surges but fails to idle smoothly to the point of dying. 2)I am able to drive it if I constantly pump the throttle to gain speed. At higher speeds I can drive down the road. 3)Runs rough and acts like it is running rich. 4)Code scanning returns a 44 which is a "lean" condition even though acts as "rich"

5)Oddly if I remove the electrical connection from the MAP sensor, it will idle fine and rev smoothly while NOT under load. Under load it still hesitates but I am able to drive it...hopefully not to a shop which I can't afford.

I have made the following repairs with no success:

1)New fuel filter 2)New 02 sensor 3)New Coolant Sensor 4)New MAP sensor 5)New TBI gasket 6)New Plugs 7)New Vacuum hoses

Any comments to cuase would be greatly appreciated.

Reply to
J.P. Burton
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Hi, Checked manifold vacuum leak? You can spray WD40 all around. And PCV, EGR valves.

T> On a recent trip I was cruising along at about 70mph. The check

Reply to
Tony Hwang

Carb cleaner works as well, and doesn't leave an oily residue behind when it evaporates. When the cleaner hits the vacuum leak the engine RPM changes.

JazzMan

Reply to
JazzMan

Reply to
J.P. Burton

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