View Full Version : 1999 f350 powerstroke power loss

February 11th, 2011, 08:00 PM
1999 f350 7.3 powerstroke, getting major loss of power when going uphill either with or without a trailer, max or 15 -20 mph, seems that it doesn't know when to shift. need answers.

February 12th, 2011, 09:13 AM
so many items to cover as fuel, exhaust, ignition
is the CEL on ?
did it just happen or has it been getting worst ?

February 14th, 2011, 05:23 PM
started about a year ago, we had it serviced and the said there were some pressure problems with the turbo so they changed out some fittings and tightend everything up including 2 fuel lines that were leaking, I could break out the bill for more detail, they also said the tranny needs to be serviced, after that it ran fine until about 2 weeks ago, it started doing it again, the tranny still hasn't been serviced and its due for the fuel filter to be changed also.

also not sure what the cel is

February 14th, 2011, 05:28 PM
and the check engine light is not on.

February 15th, 2011, 08:13 AM
Sounds like trans slippage to me.

February 15th, 2011, 08:43 AM
do the tranny & fuel filter and see what happens

there are a couple of options on the tranny
dealer flush, usually without filter change
DIY fluid & filter change at home, this will require more work on your part, which involves more than just dropping the pan

can provide details for the DIY flush if needed

February 17th, 2011, 08:21 PM
but if it was trans slippage wouldn't it be doing it all the time not just on hills?, or is that just when its most obvious when its under a load?

February 17th, 2011, 08:23 PM
yes info on the DIY flush would be helpful.

February 18th, 2011, 12:18 AM
2 things I've noted are practically a must for the 7.3's.

1) Pyrometer, you NEED to know your temps especially if you have a tuner
2) Boost gauge. Helps verify your getting your 18# average boost.

February 18th, 2011, 12:32 AM
check your fuel bowl for leaks its comon on the 7.3L and it will really kill power if its leaking.

July 8th, 2011, 09:18 AM
Start with the fuel filter ....
While you have the filter out look inside with a really bright light for stress cracks comn problem clean really really good install new filter clean all around the area start it and look for leaks ....
Also check all of the fittings going to and coming from the air cooler to the turbo ....
I have seen several trucks with this problem most of the time its fuel filter ....
A few were a inline high presure pumps going bad .. I dont think its that once they start going bad its a pretty sudden death ....
Do you keep up on the oil changes ????????
Do you add anything to your fuel ????