97 T-Bird wont perform

Ok guys, I've been working on this 1997 Thunderbird with a 4.6L V8 for 2 weeks now and cannot figure this thing out. The problem is that when you push the gas petal to the floor the engine starts to bog way down like it is not getting enough fuel. Oh yea the only codes that come up are bank 1 & 2 are running lean.

The fuel filter has been replaced it was clogged pretty bad, the fuel preasure is great now (Checked with fuel preasure gage). Cleaned all injectors. New Plugs and wires, and it still runs the same.

Any thoughts would be helpful guys, Thanks.

Ok "bog down" like the rpms drop or "bog down" like its not shifting down and doesn't accelerate at all?

If its the first one I would start at cleaning the MAF (which isn't a bad thing to do anyways), the second one start at your throttle positioning sensor, unhook the wire lead to it and hook a multimeter up to it and set it to ohms (someone correct me if I'm wrong) and check for a smooth increase throughout the motion of the throttle.

*after a minute of thinking about check the TPS first...

"In the end there can be only one... Obamrolet"

Check if the converter is plugged. Unbolt it in the front and pull apart about 1 inch. If you then have full power buy a new one.

Check if the converter is plugged. Unbolt it in the front and pull apart about 1 inch. If you then have full power buy a new one.

Sorry forgot to tell ya'll but we have already removed the exhaust and found out that it still performs the same.

Ok "bog down" like the rpms drop or "bog down" like its not shifting down and doesn't accelerate at all?

If its the first one I would start at cleaning the MAF (which isn't a bad thing to do anyways), the second one start at your throttle positioning sensor, unhook the wire lead to it and hook a multimeter up to it and set it to ohms (someone correct me if I'm wrong) and check for a smooth increase throughout the motion of the throttle.

*after a minute of thinking about check the TPS first...


"Bog Down" as in a older carburated motor that has the timing retarded to much. You stomp it and the rpms go to 3000 and then hold there like a rev. limiter is holding it and then 2 secounds later vrooommm your gone.

Also have already cleanded the MAF sensor and it didnt help the ohms going into and though the throttling of the car are perfect according to the specs I got from Ford.

The one thing that is weird though is that when I hold the car to 4000 rpms my scan tool only shows the engine running at 2250 rpms......Maybe a problem with the computer?

What I mean is the cars tac. is reading 4000 rpms and the motor does sound to be doing 4000 rpms but the reading my scan tool is getting from the computer is only 2250 rpms. Is the a way to test just the computer instead of just replacing it?

Did you unplug the sprout and check base timing?

Did you unplug the sprout and check base timing?


No I have not but it seems like that might be the next place that I turn.

Well just wanted to let everyone know that the problem has been found and has been fixed. It turned out the intake gasket had 2 leaks on it causing the intake to suck in to much air. Both if the leaks were on the bottom side of the intake and were only able to be found once we hooked the engine up to a smoke machine. But at least we finally found it. Thanks agian for all your help in trying to find an end to this problem.

Thanks for letting us know what you found to be the problem, Brad.