I have a 1999 V-10 w/ 4R100 trans. With no load at 65mph the truck intermittently will refuse to downshift and almost die on the smallest of hills. Then if I pull over, turn off truck and restart, I can make the hill (maybe). Once it starts to bog down, manual downshifting makes no difference. It will downshift but bog and cough.

It eventually (hour?) threw a service engine soon light but it went off after restarting. No blinking OD. Shifting otherwise normally.
It does seem to hiss after turning it off, like there's a backpressure issue. I'm dying to pound out the cat if that's the culprit.


1999 F-250 V-10 crew cab w/ 232K miles approx.

 

Your best bet is to make the CEL come back on and run the codes. Or try running the codes now, especially with a scanner that reads pending codes.

I'm lead to believe its a fuel issue or a computer issue. When was last tune up?

 

I just bought it last year and know of no tune up history.
It was intermittent. Even if I floored it on a flat straight, it would bog, no shift.

 

Have the codes ran. And check out the COP boots and get a glimpse of the plug to see if they look old.

 

I dont know if i can get it to throw the code again w/o risking an accident - again.

 

I wouldn't suggest trying to make the CEL come back on again. But still just get a scanner and scan the codes. Autozone and advance do it free

 

Thanks for the advice!

 

Just a hunch, but could your catalytic converter be clogged?

Try disconnecting your exhaust ahead of the catalytic converter and going out for a quick test drive. If it is the issue, your power should be restored.

 

When the CEL came on a code was stored in memory. It will stay there for about a month after the last time the light was on. There is no need to try and make the light come one again, the code is available.

 

Thanks Mark. Your advice, in particular, has saved me tremendous amounts of time and money. Greatly appreciated!

 

Thanks for the clarification Mark. I didn't know they were stored that long!