4.6 Bogs Down at WOT

[David Bell]

I have a '94 with a 4.6 litre and 62k miles. Recently, it began to bog down under wide-open-throttle accelaration. This is not just a stumble but a 'whoa, what's going on here' kind of thing. 3/4 throttle or less seems perfectly fine. Occasionally, I get a noticable idle miss that may even kill the engine but most of the time it runs like a watch. The engine check light is NOT on.

I guess the range of possiblities is large but I was hoping this might be a common problem that someone recognizes.

Any insite appreciated.

Thanks

 

[BADMUDE]

I had the same trouble.....turned out to be my plug wires....to much resistance to take the voltage...

Good Luck!

 

[Asher]

David,

I assume your have ruled out the fuel system? If not, has the fuel filter been serviced recently? Have you done a pressure and volume test on the electronic fuel pump?

My 94 had a similar issue that drove me crazy. It progressively got worse until, it would stall at a signal light and not restart for a couple of hours. No check engine light. I ran OBD-2 checks and nothing was wrong. The fuel pressure was just at the low end of specification during a load test so I did not jump on the pump.

It finally died completely and was then easy to find. If it was wires, [been there too] then the idle quality gets REALLY bad and you should experience a misfire condition across a great power band. My 2 cents is that you may have a fuel starvation problem in light of no codes.
Asher

 

[David Bell]

The fuel filter is relatively new. Also the plugs and wires and one of the two Oxy sensors have been replaced recently. A check light was on until the Oxy sensor replacement.

You could be right about the fuel pump though. What would be an easy way to test it?

Thanks,

 

[96TBird462369]

i have a 1996 t-bird 4.6 i had the same thing happen to my car.....new fuel filter, plugs, wires, and pump. with mine it was the mass air sensor tube. Go behind the airbox to the samplint tube...take the top off that holds the elements in the tube. If there is n e dirt on it then very carefully user a plain Q~tip to wipe it off.....if it is all covered up than u cant accuratly read your air flow.