How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site. Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Mazda Ed Your Own Question
Mazda Ed
Mazda Ed, Auto Service Technician
Category: Ford
Satisfied Customers: 2223
Experience:  ASE Master Technician, Mazda Master Technician, GM and Ford factory trained. 15 years experience.
Type Your Ford Question Here...
Mazda Ed is online now
A new question is answered every 9 seconds

2003 ford escape: v..rough idle..boost..a small loss in acceleration

This answer was rated:

I have a 2003 ford escape v-6 that has a recently developed power loss, rough idle, loss of power brake boost problem. It started out a few weeks ago as a random problem where it just had only a rough idle and a small loss in acceleration. Then the vehicle was fine. It has progressed into the current problem where the vehicle cannot exceed 20 mph no matter what you do. The check engine light is on and i had the codes run and was given P0405 - EGR low voltage. I feel like this a vacuum leak b/c of the loss of the brake booster. Could it be an EGR issue? I don't want to go replacing parts but I did a quick search and could not find a vacuum leak.



These could be related or not... it's hard to tell at this point. The P0405 is usually a defective DPFE sensor, but normally that would not cause all these other issues. I once had a defective brake booster which caused a vacuum leak with hard brakes and a rough idle. You can test this by removing the vacuum hose from the booster and plugging it off to see if the idle corrects. An area common for leaks is the intake gaskets. The easiest way to test this is with some carb cleaner spray. Spray it all around the intake area and listen for a change in idle indicating it is sucking the spray up through the leaky gaskets. Another area to check is the PCV hose elbow coming from the intake. These have a tendency to get soft and suck closed or split open.

Customer: replied 7 years ago.
I had already checked the brake booster and ruled that out. The loss of power and driveability really has me stumped. Would the intake gaskets leaking or the pcv hose cause the severe loss of power? I also recently changed the fuel filter. Could it be a fuel delivery issue? After changing the filter i did notice that the idle was higher and would not drop from 1500+ rpm to 8-900 rpm very quickly and sometimes the vehicle would stall but would always start right back up. Here are more details on the evolution of the problem...4 days ago, the car started up and was running rough - the check engine light flashed at me but never stayed on. The weather was cold and raining. I drove it 5 miles, turned it off and it sat for 10 minutes. I started the vehicle up again and it drove fine. It drove fine later in the day and the next day too. It sat for 2 days and when i started it up this morining it had a rougher idle and noticeable power loss. I drove it 5-6 miles, the check engine light was now on fully. I got to my destination and left it for about an hour. When I drove home, the check engine light was still on and i could not accelerate quickly or get the vehicle over 40 mph. I got home and let it sit for an hour with the battery disconnected to clear the check engine light. I started it up again and drove it to the autoparts store to put it on the computer. Now it would not exceed 15-20 mph and was VERY sluggish. I am trying to figure out how the problem is getting worse so quickly. Hopefully these additional detials help...
Customer: replied 7 years ago.
I sprayed the intake with cleaner, no change in idle. The hose to the pcv valve seems to be in good condition too. It is not soft and the insulation is all intact. Other ideas?

Ok, the flashing light is telling you there is a serious misfire and to not drive the vehicle. Since you continued to drive with the serious misfire it could have damaged the catalytic convertor. The raw fuel will cause the convertor insides to melt. This will cause the convertor to plug up and restrict the exaust. In turn this high exhaust backpressure will cause a serious lack of power and lower engine vacuum since the air has no where to exit. This could have been a problem that started out as a simple bad coil pack (they fail all the time and are most noticeable in wet weather) and progressed into a more costly issue. There is a good chance that the EGR code is setting due to the high back pressure in the exhaust. The best way to check is to remove an oxygen sensor and use a back pressure gauge. I figure you don't have this tool, so you can try loosening the exhaust at the convertors and see if that restores engine power.



Mazda Ed and other Ford Specialists are ready to help you
Customer: replied 7 years ago.

Great advice, I took it apart and the front (light off) converter was plugged. I think the rear converter (not the light off) on the exhasut pipe has a partial restriction too. The engine seems to be more sluggish with that part of the exhaust hooked up. One thing that I noticed is that when the vehicle is in park, you can't rev the engine passed 4000 rpm. Is that a rev limiter or is their a possible fuel delivery problem? The engine seems to pull strong to 6000 when driving it down the road. Thanks so much for your help!! I will accept your answer as soon as I hit the reply button.

There is a park/neutral rev limiter but I don't know what the actual number is.... You may want to contact Ford about a convertor warranty, they should be 8 year 80000 miles.


I would say the misfire caused this problem and 99% of the time a bad coil is what causes the misfire! I see them go bad all the time.

Customer: replied 7 years ago.

It has been a few weeks and the car is giving me trouble again. The exhaust was fixed, all plugs were replaced, along with the fuel filter, air filter and intake gaskets. I am now getting the following codes P0300, P0304, P0305 and P0316. Any ideas? I have not replaced any coils yet. The problem arose after the vehicle sat over a cold and very rainy weekend. I realize this is a new question but I wanted you to see the history from the older posts. I will gladly pay you for help with this question.

What was fixed on the exhaust?

Typically if the misfire starts during or right after raining you have a problem with the coil. You can remove the coils and look right where the electrical connection is. You will probably notice a small crack from the plug area heading to the center of the coil. I believe this is where the water enters. With the coil removed, remove the rubber boot and twist off the spring. You will likely see a small amount of corrosion on the end of the spring and also on the tab sticking out of the bottom of the coil. This is a sure sign that moisture was in there. Since the coil is an electronic device.... water is a big no-no. If you see any of these signs then replace those coils. If everything looks clean and shiny then swap the #3 and #5 coil and see if the misfire change to cylinder 3. If it does then you know you have a bad coil.