What Causes My Ford Escape To Misfire?

Over the years, I've identified 3 major issues that are usually the root cause of a misfire condition on a 3.0L Ford Escape (Mazda Tribute) and more than likely your Ford Escape (Mazda Tribute) is experiencing one of them. They are:

  1. A bad ignition coil.
    • The coil just stops sparking due to age.
    • A bad COP coil will definitely set a misfire diagnostic trouble code.
    • This is usually the easiest issue to diagnose and resolve.
  2. Oil leaking into the spark plug tubes from the valve cover gaskets.
    • The COP coil and spark plugs are centered in the middle of the valve cover gasket and the valve cover gasket is the one tasked with keeping oil from leaking into the spark plug tubes.
  3. Intake manifold gasket leaking vacuum.
    • This usually causes a P0300 random misfire code.
    • Ford, in its infinite wisdom, decided to use plastic and rubber gaskets for the intake manifold and the intake manifold plenum on your Ford Escape (Mazda Tribute).
    • Over time, these harden and become compressed to the point that they stop sealing.
    • When this happens, you'll experience a rough idle condition at engine start up, but once the engine warms up (and the gaskets warm up, loosen up and expand), the problem goes away.

Where Do I Start My Misfire Troubleshooting Tests?

You're mission (and the purpose of this article) is to find out if the misfire code is due to a lack of spark in a specific engine cylinder. It's as simple as that. As mentioned before, what complicates this a bit, is the fact that 3 of 6 COP coils are under the plastic intake manifold plenum.

So what's the first thing you should do to start troubleshooting a misfire on your 3.0L Ford Escape (3.0L Mazda Tribute)? It's to check for misfire trouble codes with a scan tool.

If you're fortunate enough, your Escape will have a misfire code to let you know exactly which engine cylinder is the one missing. If your 3.0L Ford Escape (Mazda Tribute) doesn't have any misfire diagnostic trouble codes, don't worry, this tutorial will still help.

OK, to get this show on the road, choose from one of the following:

TEST 1: I Have A Misfire Code Or Codes

How To Test The Ford Escape COP Coils (Troubleshooting A Misfire)

If you have a misfire code or misfire codes, half the battle is over.

What you now need to do is to use the image on the right to ID the cylinder that's being accused of misfiring.

With this information, you'll be able to see find out if the misfiring cylinder is on the bank that's underneath the intake manifold's plastic plenum or not.

  • P0301 accuses cylinder #1 (under plenum).
  • P0302 accuses cylinder #2 (under plenum).
  • P0303 accuses cylinder #3 (under plenum).
  • P0304 accuses cylinder #4.
  • P0305 accuses cylinder #5.
  • P0306 accuses cylinder #6.

If the misfiring cylinder (identified by the misfire code) is underneath the plastic plenum (these would be cylinders #1, #2 and #3), you're looking at having to remove the plenum to check for the exact cause of the problem.

If you have a P0300 (Random Misfire) code, then you need to treat this as NOT having a misfire code and your starting point is here: TEST 2: I Have No Misfire Codes.

CASE 1: The misfiring cylinder is underneath the plenum. This means that you have one of the following DTCs P0301, P0302, or P0303. Go to: TEST 5.

CASE 2: The misfiring cylinder is NOT underneath the plenum. This means that you have one of the following DTCs P0304, P0305, or P0306. Go to: TEST 6.

TEST 2: I Have No Misfire Codes (or a P0300)

If you don't have misfire codes stored in the PCM's memory or if you have a P0300 Random Misfire Code, then you're gonna' have to do some exploratory surgery and check for these specific things:

  1. Is engine oil leaking from the valve cover into the spark plug tubes?
  2. Is the plenum gasket (which is made of rubber) leaking?
  3. Are the COP coil sparking or Not?

This is gonna' involve removing the intake manifold plenum to get to the three coil-on-plug ignition coils that are in the back of the engine but before you do, I recommend that you test the front COP coils for spark with a spark tester.

I want to emphasize that testing the front COP coils for spark needs to be done before you remove the plenum (to get to the ones in the back). Why? Here are the two main reasons:

  1. The COP coils for cylinders #4, #5, and #6 need to be cleared of being bad right off the bat.
  2. You'll also find out if the front valve cover is leaking oil onto the spark plug tubes because if it is, then the rear valve cover will also be leaking oil into the spark plugs.

OK, let's get started with the very first test in the next page. Go to: TEST 3: Testing Cylinders #4, #5, #6 For Spark.

Ford Vehicles:
  • Escape 3.0L
    • 2001, 2002, 2003, 2004, 2005, 2006, 2007
  • Five Hundred 3.0L
    • 2007
  • Freestyle 3.0L
    • 2005, 2006, 2007
  • Taurus 3.0L
    • 2000, 2004
Mazda Vehicles:
  • Tribute 3.0L
    • 2001, 2002, 2003, 2004, 2005, 2006
Mercury Vehicles:
  • Mariner 3.0L
    • 2005, 2006
  • Sable 3.0L
    • 2000, 2004