loss of power when reaching speed of 65 mph

loss of power when reaching speed of 65 mph

Postby rockstar627 [OP] » August 30th 2016, 8:41pm

loss of power at 65 miles per hour
...that is when I drive from stop to highway speed this has started a few months ago

when I ease of the throttle and drop my speed
...the power returns and then I can easily accelerate to 70 or 80 miles per hour without any trouble

NOTE: I recently changed the plugs and wires and it runs beautifully
... and just yesterday I changed the cat
... disconnected the battery to reset computer
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Re: loss of power when reaching speed of 65 mph

Postby Autosmith » September 6th 2016, 1:19pm

Have a look at the spark plug wires, make sure the coil wire isn't grounding against the trans dipstick tube. Would be great if you could see what fuel pressure is doing when this happens (got a tester)? I would have guessed cat but you replaced it. How about the other end of breathing; what's the intake side like? Filter good? Have you tried gently cleaning the MAF wire with a little rubbing alcohol and a q-tip? Over-oiled K & N's will coat the MAF hot wire and cause this issue. If she still gasps I would go back to exhaust, can you put a pressure test point in the o2 sensor port - any more than 3psi in the exhaust and you have a restriction rear of the port (collapsed pipe, muffler baffle, cat, etc...).
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Re: loss of power when reaching speed of 65 mph

Postby mmadden55 » September 6th 2016, 3:51pm

I agree likely dirty MAF wire or air filter or both.
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Re: loss of power when reaching speed of 65 mph

Postby rockstar627 [OP] » September 7th 2016, 8:21pm

dirty intake was cleaned and made a huge difference
... occasionally acts up though and doesn't want to shift into overdrive at 65 mph
Original Poster [OP]
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rockstar627
Fueling (1/4 tank)
Fueling (1/4 tank)
Years of Membership: rockstar627 has been a member for 6 full yearsrockstar627 has been a member for 6 full yearsrockstar627 has been a member for 6 full yearsrockstar627 has been a member for 6 full yearsrockstar627 has been a member for 6 full yearsrockstar627 has been a member for 6 full years
Posts: 27
Topics: 7
Images: 13
Joined: July 2014
Gender: Male
Alias (AKA):
Van Model Year: 1998
Van Make/Model: GMC Safari
Extra Info: AWD V6 white passeng


 
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