4.0L OHV & SOHC V6 Tech General discussion of 4.0L OHV and SOHC V6 Ford Ranger engines.

99 4.0 Ford Ranger Low Power Slow Acceleration

Old 11-01-2018
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Join Date: Nov 2018
Location: Meridian
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Icon4 99 4.0 Ford Ranger Low Power Slow Acceleration

I've been having some problems with my 99 Ford ranger (4.0 v6 4x4) regarding power and acceleration. It has around a 20 second 0 to 60 at full gas and I am at a loss for why this is happening. I have replaced the air, fuel, and oil filters and all 6 spark plugs around 1000 miles ago and the oil. It seems like the engine is struggling and by the video you can probably tell that the engine seems to sound like it is working very hard but the truck goes basically nowhere. If anyone can help it would be greatly appreciated. Thank you

Youtube video of the 0-60:
Old 11-01-2018
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Join Date: Jan 2014
Location: Vancouver, BC
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Welcome to the forum

First check if throttle cable has stretched
Press gas pedal down to the floor and use a stick against the seat or a weight to hold it down

Open hood and see if you can manually open throttle a little more

Google: Ranger throttle cable mod
Easy fix

On level ground get rolling about 5-10mph and shift to Neutral
see if brakes or anything else seems to be dragging speed down

Vacuum gauge is one of the better tools to have, $20
Check engine vacuum at idle, should be 18-21", lower could indicate compression problem

REV engine, snap throttle open all the way then let it snap closed
Watch vacuum gauge, it should drop below 2" then instantly come back up to 18", if it's slow to drop and slow to return then you have a partially blocked exhaust
Collapsed Cat or muffler internally
If all the exhaust can't get out then all the new air/fuel mix can't get in, so power is limited to the amount of air/fuel that can get in
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