Contour Enthusiasts Group Archives Forums General General Car slow as dog sometimes

I admit defeat. I cant figure it out. I've changed everything I know to take care of the problem. Plugs, wires, O2 sensors (upper ones), fuel filter, clean air filter...cleaned upper and lower manifold, had injector flush done. Everything! Oh the car is a 1998 Contour SVT with 176,000KM

There is no fault light or anything coming up either.

Sometimes for no reason what so ever, the car starts to get sluggish after 10 mins of driving (even highway driving).
Symptoms:

-The gas pedal starts to feel like a spong instead of feeling nice and firm. The response on the throttle is poor.

-Even though I can feel and hear the secondaries open, the car just doesnt accelerate like normal. It even revs up slower and in 3rd and 4th gear past 6K it will start to ping.

-While the car is feeling slower than usual, I can hear a very slight hissing sound while I'm on the throttle, even part throttle. The sound is a deeper hiss which may just be the air rushing into the engine which I'm hearing...but I dont hear this when the car is feeling strong. The filter is a K&N inside the stock SVT airbox.


All this stuff tends to happen more I believe on days which its humid. I dont think its heatsoak because when the car is running right, a few minutes on the highway gets rid of any slight power loss I may feel. Also when the car is acting up, my power loss is significant enough that I may lose to a stock automatic NEON!
Note that I can stop the car. Let it cool down and on next startup it may not do this...

Also its very intermittent. I may turn off the car and let it cool and then drive for the next 4 hours with no incident. Sometimes its a dog right at startup but most times its a gradual thing. When the gas pedal starts to feel more spongy, then I know the car is a dog.

The car has run 15.40@90 with a filter, no resonator and a modified stock y-pipe...and a full tank of gas and a smallish stereo Oh my dyno says I have 164HP and 148lbs of torque at the wheels. This is obviously when the car is not acting up.


So anyone know of any sensor or part that can make the car act funny like this? Is it also my imagination but I can swear that the car makes more power (not much more but enough to notice) on a full tank of gas than when its close to empty....



Thanks guys

When the engine heats up metal contacts may "move apart a little" and be a very hard problem to find.

I have two suggestions.

Coil pack and TPS. One of these two item may do what i described above and be very hard to get them to do there problem long enough to pin point the problem.

Good luck.

Eric

I'm going to check them out. The bad part is not knowing...and having ford say that the car is fine. That drives me nuts.