Hi guys,

I'm new to the forum and new to Fords and Escapes...and hoping to learn something from people with more experience. In this case, I'm trying to figure out if my poor acceleration is due to a blocked cat, ignition issues, or something else that I haven't thought of....

I just bought a 2002 Escape XLT, 3.0L V6, auto., 4X4. The engine runs well, no misfires or roughness at idle or otherwise; but the acceleration is not what it should be. If driving normally, accelerating like I'm being fuel-conscious, everything feels normal while accelerating anywhere up to 55-60mph. If I try to accelerate faster (like merging onto a freeway), it feels like I'm hauling a lot of weight behind me. The vehicle will get to the speed I want it to, but will take a long time to get there. The transmission isn't slipping, and the tack needle seems to be at the appropriate range for acceleration (it doesn't top out low like some people report when cat. is blocked). No misfires while accelerating or maintaining any speed. No check engine light (CEL). Air filter looks clean.

I have no experience with Ford engines or with this kind of acceleration issue. Do you guys have any thoughts, or know of any things I can do to troubleshoot?

Thanks!

 

Make a note of the rpm when a particular upshift occurs, such as the 2-3 or the 3-4 when you accelerate gently. Do the same acceleration, when in 2nd or 3rd, and then press down firmly on the gas pedal harder. If it shifts at the same rpm, you may need to have the linkage adjusted. If you cannot get the transmission to 'kick down' from, say, 4th gear to 3rd when you want to accelerate by pressing on the gas pedal at a reasonable speed {say 40-50 mph}, and have the rpm's increase, it is just another sign that the linkage needs adjustment, or you have a problem with the speed sensor(s), or the TPS or other component.
The transmission should kick down when you are climbing a slight hill, and the speed falls off, but you don't back off the throttle. I have had mine on cruise, and had it downshift in the rolling hills of OK travelling 65mph, when the speed fell off just a bit. I tired of the irregular rpm jumps and disengaged the cruise rather than have the engine roar all the time.
tom

 

How many miles are on the car?

 

TomW: I don't think the RPMs are the same at each shift for slow acceleration vs hard acceleration, but I'll pay closer attention to that tomorrow to be sure. The transmission does kick down when going up hills as you described.

tcesni: 129k+ miles on the car.

 

Has the exhaust system ever been replaced? I am thinking that the resonator or muffler might be partially clogged and restricting the engines breathing ability.

 

I have a 2001 with same amount of miles. Whats a good way to figure if exhaust is clogged or if its been replaced? I'm second owner, but the previous owner is not available for asking maintenance questions of.

 

This problem seems to be the front cat on the v6 engines. The 2001 escape I recently purchased was so bad that the guts of it were blown all the way back to the third cat that is in front of the muffler.

 

I guess my question is how to tell if cat is blown without opening it up?

 

Take the o2 sensor out and look in it. If there is any stuff there it is definitely bad and you should take the crossover pipe off and look in the rear cat.

 

I just had O2 sensor replaced ( downstream) and mechanic said it was real dirty. Would this be what you are meaning? Also, I've been noticing gas milage is a little low lately. Was getting 24 highway, now having problem getting 22 highway. Would that do it?

 

If your converters are not working properly, the down stream O2 sensor would be tattling to the computer. The code words would be along the lines of "catalytic converter efficiency not up to standards". If one of the converters has failed, I would think you would get a CEL lit on the instrument panel.
You can check for back pressure by removing an O2 sensor, installing a pressure gauge and then running the engine. If the converter, muffler or resonator are plugged, the pressure will build as the engine runs and you will seem to have less power when driving.
I would check that the thermostat is working properly, the ECT and ACT sensors are within bounds as the coolant temp and reported incoming air temp affect how the computer rations fuel. The MAF and MAP can also have effects on mileage.
tom

 

Hmm, most of those tests are above my competency at this point. Guess I'm gonna have to call my mechanic and schedule a troubleshooting session. Unless any of those tasks can be done by a weekend guy like myself...

 

Hey guys, sorry for not replying sooner....I'm not getting email notifications for replies for some reason.

Anyway, the problem persists. There seems to be a "normal" flow of exhaust out of the tailpipe ( as much as I can tell by watching it in the cold, or by putting my hand by the tailpipe). I just changed the fuel filter; I'm not sure it made any difference.

The transmission shift points are different RPM-wise for gentle vs. hard acceleration.

Another detail that I forgot to mention in my first post is that the rear exhaust manifold has a leak. It hisses under acceleration heavier than "gentle." This had me wondering about the rear manifold/cat being blocked....but there is still no check engine light. No codes pending, either.

The RPM's will come up as high as 4500 ( I stop there, for fear of hurting the engine ), but not very quickly. Again, no discernable misfiring going on.

 

Problem solved...rear catalytic converter plugged. I drilled a few holes inside to increase flow, and now the vehicle accelerates well. Although not a permanent solution, at least it's drivable until the permanent fix is done.