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99 burban wont shift under hard acceleration

1765 Views 6 Replies 3 Participants Last post by  murdog94
Hey guys, Im beating my head against the wall... 99 burban Z71 shifts fine unless you are in the throttle. no codes are set or stored and the timing is correct. ckp and cmp both check out. No trans codes are on ether. when under hard acceleration you have to let up so it will shift to next gear. No it does not shift hard. Fuel pressure is 55psi at idle and bleeds down to 40 in about five min after shutting it off. Changed the fuel filter and still has same pressure readings. Does the low pressure have any thing to do with the shifting issue? Where do i go from here? Please help.
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Hangs out around 3600 rpm and wont shift. i do believe its the TPS. going to test it rite now. ill update in a while. Thanks for the insight, Mike.
So it was not the tps. It is still hanging out around 35 to 4500 rpms and won't shift unless I let up. Beginning to think its a selenoid in the trans the is hanging up. It does this in every gear.
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