Truck Problem

[lenard_hester]

I am having an issue with my truck and thought I would check here to see if anyone might have a clue what is happening. When at WOT on the 3-4 shift it sounds like it is either trying to downshift again, or it is trying to shift twice (kind of hard to explain). When this happens, it is like the engine shuts off or something. The RPMs will still be up and when I hit the gas pedal the supercharger will wind up, but there is no engine response (I assume this happens because my momentum is causing the engine to revolve) I then have to shif into N and turn the key off and restart the engine. This happened to me twice on Saturday, but I could only do it those 2 times by accident. Every time I have tried to reproduce it after that has failed. If anyone knows what may be causing this I would love to know so I can fix it. The only thing I could think of would be something with the fuel system. And just for reference to that I changed the fuel filter about a month and a half ago.

[rickgig]

I've had a fuel filter get trashed in less time than that... however, fuel starvation would occur in lower gears too not just WOT in 3 and 4th...

What happens in the other gears?

[lenard_hester]

In all other gears it drives like normal, it runs as smooth as a baby's bottom. This only seems to happen at WOT. I am pretty sure it has only happened on the 3-4 shift, but it could have happened on the 2-3 shift. As I said, I only did it twice on accident, and I couldn't reproduce it when I wanted to see what was happening.

[Sixpipes]

What mods do you have? :cool:

[Beaudee]

Had trouble with an 02 sensor that never threw a fault, and acted like trans trouble.It intermit. dropped 4 cyls.Only did it when i stomped on it.Problem fooled everyone @ dealership.Took ford eng. to fig. out prob..Good luck!!!!

[lenard_hester]

Sixpipes:
My mods are a 4lb lower pulley, Airaid CAI, Superchip programmed by Terry, and Flowmaster mufflers.

Beaudee:
Is there any way of detecting this, or will need to get a Ford engineer to find out?

[Beaudee]

I am not sure how they found the problem but they put onboard monitor and drove the truck to get it to duplicate.They told me the engineer had equip. they didn't have.They finally traced it to 02 sensor dropp. 4 cyls. interrm..Swithced 02 sens. and then other side acted up.Problem solved after 2 weeks in shop, 140 miles on my brand new truck.They where gona give me a new truck cause they couldn't find the problem.The onboard monitor started them in the right direction.The ford dealer had that, but didnt know why it was dropp. 4 cyls. intermitt..My truck would lose power and act like it wasnt down shifting.Mostly did it @ wot. and let off.Noticable when you punched it and the hit the breaks,sometimes would miss and backfire.Imagine buying a brand new L. and telling them it stumbles when you floor it and let off!Neverless they broke my truck in for me.Might not be your problem but 02 sensors can go bad without a engine light or a code fault in the comp. and drive you nuts with mysterious problems.Cheep fix though. :tu: Good luck, and most dealers have the onboard monitor.

[lenard_hester]

Thanks for all the info. I am going to try to reproduce it some more to see if it was just a fluke or if it is a real problem. If I can reproduce it, I may just replace the O2 sensors just to see if it fixes it. My problem sounds very similar to what you are describing.

[lenard_hester]

ok, it has been a few weeks, and I have not been able to reproduce the original problem, but I did come across another seemingly related problem. Every once in a while (very rarely actually) when I go over a sharp bumb like a bad set of train tracks, or the rail for an entrance gate to an apartment complex, my engine will shut off after going over the bump. As I said before, this happens rarely, but it does happen. My though as to why it may be related is that maybe before, the "bump" in the 3-4 shift was enough to shut the engine off similar to what happens at the train tracks. I hope I have made this clear enough. If anyone knows what may be happening, I would love to know so I can rectify the issue.

Thanks all.

[99WhiteBeast]

ok, it has been a few weeks, and I have not been able to reproduce the original problem, but I did come across another seemingly related problem. Every once in a while (very rarely actually) when I go over a sharp bumb like a bad set of train tracks, or the rail for an entrance gate to an apartment complex, my engine will shut off after going over the bump. As I said before, this happens rarely, but it does happen. My though as to why it may be related is that maybe before, the "bump" in the 3-4 shift was enough to shut the engine off similar to what happens at the train tracks. I hope I have made this clear enough. If anyone knows what may be happening, I would love to know so I can rectify the issue.

Thanks all.

Just a shot in the dark here but is your negative cable on the battery tight? I've seen some this described in this thread with a loose negative before.

[Sixpipes]

Make sure your computer is secured to the truck and your chip is taped in as well. Sounds like a loose CPU or chip. :cool:

[Tex Arcana]

Lenard, what year is your truck?? I konw this might not apply, but back when I had my '97 Lariat, it died on me when I tried to start it, and lost total power. Turns out that a cable that ran down the passenger side of the engine was rubbing on a bracket near the header, and it shorted out, and took out the battery. Kind of a long shot, but worht looking in to...

[lenard_hester]

My truck is a 99. I will look into all of these, they all sound like feasible problems. As far as checking ad taping the chip in, how do I remove the computer to look at this?