Misfire?

JUNIT0483

MEMBER
2009 FORD ESCAPE
3.0L
V6
4WD
AUTOMATIC
172,800 MILES

I had a misfire a few months ago. Cylinder 1 had a bad coil. I replaced all 6 COP's and plugs as well as new gaskets and fuel injectors since I was already in there. About a month went by and the misfire returned except this time it isn't producing a CEL. 2 things I've noticed that seem unusual. If the vehicle is positioned downward on a steep hill it is guaranteed to cause a misfire. However, it will misfire at other times as well. The misfire can last for short periods or long periods. And the second thing is when the misfire occurs, the A/C unit will not blow cold anymore. When the misfire goes away the AC/ blows cold again.
Any insight would be appreciated.

1 Reply

JACOBANDNICKOLAS

MECHANIC
109,755 POSTS

Hi,

If the computer senses a misfire, it will cut the AC to save power. As far as the misfire, if there is no check engine light or code stored, you may want to consider testing fuel pressure. Also, if you have it facing downhill and it happens, it could be due to a low level in the fuel tank. The pump is positioned toward the rear.

Start by testing the fuel pump pressure to make sure it isn't weak.

Here is a link that explains how it's done:

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

I attached the manufacturer's fuel pressure specifications below.

Let me know what you find.

Take care,

joe

See pic below.

Image (Click to make bigger)