What power level were you running on, it sound to me like it was just slipping in 5th gear because of to much power. 5th gear dose not really like any more than 90 hp. the 50 mph limit it hit souns like limp mode due to either the trans slipping or even the engine starving for fuel but it would have thrown a p1093 code for this!
When was the last fuel filter change?
What power level? and were you under WOT when it shifted into 5th?
Later
Caleb
When was the last fuel filter change?
What power level? and were you under WOT when it shifted into 5th?
Later
Caleb