ford code po442 and engine miss

[schadd1971]

I just did the po171 and po174 fix and was easy to do but about two weeks later I got a code po 442 (small leak on evaporative emission control system) and have developed a small miss I feel at a stand still or at low RPMs while driving.............any ideas?

[busboy4]

Hi,

carefully check all your vacuum hoses on the back of the plenum. As I recall, the evap canister is on the firewall with a vacuum source to the plenum. Your slight miss and code possibly point to a vacuum leak.

[schadd1971]

ok will check it out thank you.....also having problem with heater controls it blows on window defrost despite knob position any ideas?

[12Ounce]

.... sounds like the same vacuum leak! Perhaps in the heat controls.

[wiswind]

As 12ounce said, the heater controls are vaccum driven.
Defrost is the position that they will be in with no vaccum.
The source of the vaccum is from the engine intake.....the vaccum line connects at the back side of the upper intake manifold.
On my '96, the line goes to a vaccum box that is mounted to the inner fender.....right next to the A/C accumulator (drier) canister and through the firewall into the passenger compartment.

[schadd1971]

its intresting.. im wondering if the miss is seprate from the code po442 because whhen I clear the code it stays off a while but still feel the miss, in fact no code for the miss, have read about a bum 442 code on ford windstars from ford.... is this true..????

[12Ounce]

Find and repair the leak .... then wonder.

[schadd1971]

yeah ok makes sense..thank you.....will let you know

[schadd1971]

well.the codepo442 has not come up anymore but still have a slight miss...you can feel it at idle or as you hold speed at 30 to 40 mph light on the gas petal......no problem in hard pulls up hills plenty of power.....any ideas ,,,,,,,,,,,thanks

[wiswind]

Do you have the heater control issue fixed?
If the air still only goes to the windshield regardless of selection, this could STILL be a vaccum leak issue.....but still slight enough that it is not setting a code.

Otherwise, I would change the fuel filter if it has not been changed within the past year.

I would also put a can of Berryman's B-12 Chemtool into the gas tank.
Try a can in each of the next 2 or 3 tanks of gasoline.
I would do this even if you have tried another brand of fuel system cleaner.
I had success with the Berryman's after having tried several other brands.......that were more expensive.

How old are the spark plugs and spark plug wires?

Check the vaccum line from the PCV valve to the intake manifold for leaks......mine developed a leak at the inside of the elbow right at the upper intake manifold.

I would try all these things, which are routine tune-up items, before going further.

[schadd1971]

ok will try the fuel filter and the cleaner and will check the heater control.....plugs and wires not that old ....sounds like a good starting point,,,,will keep you posted....thank you

[schadd1971]

just went over vacuum lines and found a line off and cant find where it goes ......its actually two lines , one from the firewall, i suppose from the heater the other from the plenum ,its red, and they join together to an elbow and I found it hanging loose...cant find where it goes...any ideas i plugged it and my heater controls started working ....so any ideas would be helpful....

[12Ounce]

Did we ever establish what year and engine this is?

[busboy4]

Originally Posted by schadd1971

just went over vacuum lines and found a line off and cant find where it goes ......its actually two lines , one from the firewall, i suppose from the heater the other from the plenum ,its red, and they join together to an elbow and I found it hanging loose...cant find where it goes...any ideas i plugged it and my heater controls started working ....so any ideas would be helpful....

Hi
I am coming from a '96 point of view: if there are two lines into one elbow, I think you will find it goes on the back of the upper intake manifold vehicle right. I am assuming you found this at the back of the engine compartment?

[wiswind]

You have a line that comes to a "T" with 2 more lines coming out of it?
1st one will go to the upper intake manifold
2nd one will go to the firewall and through to the heater control
3rd one will go to the vaccum resevoir box that is mounted on the passenger side inner fender, by the A/C accumulator/dryer.....between the accumulator and the fender on my '96.

As you mention that plugging the hanging line makes your heater controls work......it would indicate that 1st and 2nd are connected, so I am guessing that 3rd one is the one disconnected.