scott1984 Posted August 2, 2012 Share Posted August 2, 2012 got a 91 f150 with 300 6 cyl that has a small intermitt stumble on take off check tp map fuel pressure and all are ok tp is a little high but still in spec any help would be greatful Quote Link to comment Share on other sites More sharing options...
Mbl35 Posted August 2, 2012 Share Posted August 2, 2012 Tune up? Quote Link to comment Share on other sites More sharing options...
batmantech Posted August 2, 2012 Share Posted August 2, 2012 Throttle body gasket sucked in? Odd but worth a look is the tp shaft slot somtimes they would build up rust under the sensor Quote Link to comment Share on other sites More sharing options...
Jim Warman Posted August 3, 2012 Share Posted August 3, 2012 Is this a tip in type stumble that vanishes of you go to WOT? If so, suspect an EGR system concern. While these had an EVRV solenoid that was duty cycled, the EGR valves were positive backpressure feedback type valves. There is an orofice in the valve that can plug off causing the EGR valve to "hit too hard" in light throttle (i.e. high manifold vacuum) conditions. If you have a graphing multimeter or a lab scope, you can sweep the TPS looking for any dropouts. HTH Quote Link to comment Share on other sites More sharing options...
GregH Posted August 3, 2012 Share Posted August 3, 2012 Does it have ABS and a PSOM? I had a speedometer module that tossed out some hash on the VSS line to the PCM when the vehicle would start to move. Sometimes the PCM would interpret this hash as a speed in excess of the vehicle speed limiter. The PCM would respond by killing the injector pulse and making a stumble. The whole event would be over in less than a second. Quote Link to comment Share on other sites More sharing options...
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