Kinda got me stumped. Truck is a 97 5 speed 168k. After I let the truck idle for a bit whenever I take off it loads untill I get moving and then it cleans itself out. Also fuel milage is not the best. Twin tanks and I'm getting around 130 out of a tank. 373 rear gears. I just put in a new fuel pump and filter. Also new CPS. The truck has a NEW 3.5 down pipe and 4 to 5in. exhaust. Also open air kit. No chip yet because I use it for a beater and plow truck.
I have the same rig, (97 250 5spd) w/ the same problem... severly poor milage (130 gals/tank is 7.6 mpg btw) and thats better than what I get! And the sitting and loading up is also present... I have done alot and searched and searched here w/ no luck. I just replaced injector Orings as astab in the dark on day before yesterday w/ no change...
I can't point you in the right direction, but you are not alone...
Can anyone who has had this problem or heard of it before please chime in?
Possible damaged inj nozzle spring's.
Leaking copper inj gasket could be another. It will blow out the lower o-ring at some point in time.
All though i would check compression first.
Hmmmm... When I did Orings the day before yesterday all of the orings were OK and the rebuilt injectors I put in this summer had new orings too... I've swapped alot of parts chasing this down; fuel pump first, couple filters, pulled and cleaned tanks, screen, checked backpressure, replaced ebp sending unit and tube + fittings, checked again, ugh...
I've thought maybe the IPR could be going on it... But a compression test is the next place to go I guess, though @ 5-7 mpg and low compression I'd think Id have less power... Its not horrible yet, but it used to pull better all the same.
(1) Bad o-rings that leak oil, that usually causes a hard start when the engine is hot because the HPOP has a hard time building pressure.
(2) Trash in the valve body will cause a rough idle or stalling when you let off the throttle because it can't dump the excess oil pressure fast enough.
Ahhh, I may have symptoms of #2 also, it hasn't stalled yet, but it'll drop to 350-400rpm for a half sec after I let off the pedal--- I had wondered, can my milage and acc.l hesitation be connected? BTW, what's the valve body? hehe- new to a kid like me...
Orings are deff a rule-out, old ones were great, the new ones are just as good i'm sure...
Cool, monday the truck'll be in the shop and Ill check that first, really want somthing to work here...
appreciate it, ill update on go/no go
thanks,
woodsthing
ps, this will explain the rough accel, where is my fuel going though? It seems to burn lots more at idle than on the road- 1/4 tank less than an hour... 50 mins? no leaks- IPR'll get checked for sure, want to better understand it though.
yeah, I'm going to pull my IPR on monday... that hasn't been ruled out... do IPR issues effect milage like i'm seeing? The truck sounds nice otherwise except it acts like vengeanceent13 posted...
IPR came to mind but its something you can see in a realtime scan if its bad.
Another thought would be the barro and a mapp sensors. I would scan the range on them also.
woodsthing
Your up in alaska. Also check the EOT with the scan. It could be to cold. To cold would advance fuel and timing.
130 miles per tank means nothing. We need to know how many miles you get per gal. The fuel gage on all Fords is always wrong, you have a few gals of fuel left when the gage says empty. What you call empty will let me drive over 100 miles further probably.
When you fill up , record your mileage, next time you fill up subtract the mileage when you filled up the first time from the mileage when filling up the second time.
Divide the mileage by the number of gallons of fuel you put in the second fill up.
This will tell you how many miles you get per gallon of fuel.
ANY idle time you have will cause your miles per gallon (MPG) to go down.
If you idle your truck for an hour, it will drop the MPG by a noticeable amount.
Better MPG ?? Use summer fuel, DON"T idle at all, keep speed low.
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97 F250 SC LB 4X4 PSD TDE0, E4OD,3.55's, 285/70/16"s ,Modified fuel tank vents, 375+k headed for 500k
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