Sudden loss of power and excessive fuel consumption

LOPEZA1980

MEMBER
1999 FORD ESCORT
2.0L
4 CYL
FWD
MANUAL
172,000 MILES

When I take my car on a longer trip, not more than thirty miles, the engine suddenly loses power and I am forced to downshift to compensate for the loss. This will continue to happen until I am forced to pull over due to complete power loss, which then causes the engine to shut off. I noticed a great increase in fuel consumption when this power loss occurs. I have replaced the spark plugs, air filter, and MAF sensor as this part was recommended to be replaced after a scanner tool was used and diagnosed as this being the problem. Still having the same issue although the CEL is not illuminated this time around.

3 Replies

CARADIODOC

MECHANIC
33,874 POSTS

I have two comments of value for you to consider. First, diagnostic fault codes never say to replace a part or that one is bad. They only indicate the circuit or system that needs further diagnosis, or the unacceptable operating condition. When a part is referenced in a fault code, it is actually the cause of that code about half of the time. First you have to rule out wiring and connector terminal problems, and things like that.

You mentioned a scanner was used. The most basic thing they do is read the diagnostic fault codes. If you list the exact code numbers, I can interpret them for you.

The second thing to consider is everything you described can be caused by a dragging brake. As the sticking brake gets hot, the heat makes the brake fluid expand and apply that brake even harder. The clues are you may feel the steering wheel being tugged to one side, and there is usually a pulsing sensation in the whole car. You will also find one wheel is very much hotter than the other one after a ten-mile drive.

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Sunday, September 10th, 2017 AT 12:11 AM

LOPEZA1980

MEMBER
2 POSTS

I appreciate your quick response, at first the code being given was P0304 cylinder four misfire, so I changed the spark plugs as that needed to be done anyway. The car ran good for a while and then the same issue occurred, being the sudden loss of power and needing to pull over. Now mind you this would only occur on longer trips, of fifty miles or more, and seemed to occur more often when I used fifth gear (overdrive). If I drove in fourth gear the problem did not occur. Again the car drove fine for a while and the same problem occurred again and this time the code was P3040 Camshaft position sensor circuit malfunction. This sensor is actually the one I replaced not the MAF sensor, my apologies for the incorrect information. Now after replacing that, the car will drive good in the cool mornings but when it is hotter in the afternoon, the same issue occurs on trips of more than thirty miles. The fuel consumption has greatly increased as well. Could it possibly be the catalytic converter having buildup? The issue you mentioned about the dragging brake does not match the symptoms occurring in my car. The car will completely shut off as soon as I come to a stop.

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Sunday, September 10th, 2017 AT 1:38 AM

CARADIODOC

MECHANIC
33,874 POSTS

The next thing is to connect a scanner to view live data while driving. Of particular interest is the "short-term fuel-trim", STFT, numbers. That will indicate whether the engine computer is requesting more fuel than was programmed in as a starting point at the factory, but it will not tell you why. You have to look at the readings for the other sensors to figure out what looks suspicious. That is usually a job for an engine performance specialist.

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Sunday, September 10th, 2017 AT 8:04 PM