Flat Spot/Hesitation - Ford Forums - Mustang Forum, Ford Trucks, Ford Focus and Ford Cars

AUII_Forte · 12-05-2002, 20:51

Today I was driving out on the highway and had to open it up to pass another car. All of the sudden it has developed a HUGE flat spot! The car hesitates as soon as you hit 3500rpm.

In economy it struggles to change into the next gear, because the trans computer knows the car is floored, but the engine just doesn't want to rev to the shift point. It power the car just won't change gears when it's floored it gets to about 4500rpm (very slowly mind you) and just sits there.

It seems completely normal under 3500rpm, it pulls nicely then all of the sudden it just loses power and slowly accelerates till the economy shift point.

I recently changed the throttle cable and it wasn't doing this after I changed it, it's only started today. I put some injector cleaner and Nulon Worn Engine treatment through it earlier in the week. Surely that wouldn't be the problem. Where should I start looking?

SilverEA · 12-05-2002, 21:41

could be transmission problems:(

AUII_Forte · 12-05-2002, 21:52

But then why does the car lose power? If it was the trans the car should still rev to the limiter, but it hits about 4500rpm and won't go any further.

SilverEA · 12-05-2002, 22:01

is it a 4 speed?
The best thing might be to ask a business that deals with transmissions what they think cause it could be the electronic clutch or something coming in too soon.
I Havent heard of this problem, but the tranny could be something to think about. I'll have an ask round with some ppl I know and see what i can come up with for you.

Brent79 · 12-05-2002, 22:03

Do u mean its not kicking down?? Or is it in yer engine??? So if u held it in 1st gear and revved it up past 3500rpm then it just dies off? Hmmmm.... im thinking fuel pressure or MAP sensor fault... dunno tho... u need to explain a lil bit more... does it idle properly??

Brent

SilverEA · 12-06-2002, 15:40

Try changing your fuel and air filters. They can cause some strange problems.

Bass Crazy · 12-06-2002, 22:35

Check fuel pump pressure and flow mate.

AUII_Forte · 12-07-2002, 00:21

Ok, I think it has something to do with the fuel system. The car wouldn't start last night and after a while I figured out that the fuel pump wasn't working. I gave it a few taps with the end of a screw driver and the car started. The same thing happened this afternoon, but I've found that its not the pump itself, its a faulty connection somewhere. If I hold the wires in a certain position the pump operates, but if the wires are moved the pump stops.

But if it was a fuel supply problem wouldn't the engine misfire and stuff? The car runs fine, it doesn't miss or anything it just loses power. It kicks down and everything fine, but as soon as it hits 3500rpm, it stops pulling as hard, then as soon as it hits 4000rpm it just sits there. The trans doesn't change gears in power because the TPS is telling the computer that the throttle is wide open, but the engine just doesn't rev to 4500rpm where the shift point is.

DOA · 12-07-2002, 02:00

check your Catalitic converter. If is old, it may be braking down and partial blocked resticting you exhaust flow.

AUII_Forte · 12-10-2002, 14:28

I've changed the fuel pump, but the problem is still there. Today I'll try the fuel filter, I may even change the dizzy cap just for good measure.