cyl 4 misfire and gulping sound??

4387 Views 10 Replies 5 Participants Last post by JCZ, Oct 27, 2011

415dispatcher

Discussion Starter · Dec 30, 2010

2005 Ford Escape 6Cyl, 47,000 miles

Hello all:

The best way I can describe it is a gulping air sound around the intake. it's a deep kind of "woomp woomp" sound. It only happens when the engine is at an idle and ONLY after the engine comes up to operating temperature.

Error codes: Cylinder 4 Misfire Detected & Misfire at Startup first 1000 revolutions

Whats been done so far: Checked vacuum hoses for leaks, replaced all spark plugs (and 6 new upper intake gaskets), replaced coil pack for cylinder #4.

The problem returned immediately with the same error codes. What now? I've been all over the internet looking for the someone with the same problem. I am seeing tons of posts about cyl 4 misfires and rough idling. It seems my situation is unique with the "woomp woomp" sound and it only occurring after vehicle reaches operating temperature and only during idle. The idle seems rough no matter what the engine temp is.

I have a list of things to try but i'd like to prioritize it in the interest of saving money. The list was compiled after much internet research (escapes with similair problem):
-New Fuel Filter
-New #4 Fuel Injector
-Cleaning/Replacing IAC
-Cleaning/Replacing MAF sensor

Any Ideas? I appreciate any help, thanks!

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SUVord

· #2 · Dec 30, 2010

415dispatcher said:
2005 Ford Escape 6Cyl, 47,000 miles

Hello all:

The best way I can describe it is a gulping air sound around the intake. it's a deep kind of "woomp woomp" sound. It only happens when the engine is at an idle and ONLY after the engine comes up to operating temperature.

Error codes: Cylinder 4 Misfire Detected & Misfire at Startup first 1000 revolutions

Whats been done so far: Checked vacuum hoses for leaks, replaced all spark plugs (and 6 new upper intake gaskets), replaced coil pack for cylinder #4.

The problem returned immediately with the same error codes. What now? I've been all over the internet looking for the someone with the same problem. I am seeing tons of posts about cyl 4 misfires and rough idling. It seems my situation is unique with the "woomp woomp" sound and it only occurring after vehicle reaches operating temperature and only during idle. The idle seems rough no matter what the engine temp is.

I have a list of things to try but i'd like to prioritize it in the interest of saving money. The list was compiled after much internet research (escapes with similair problem):
-New Fuel Filter
-New #4 Fuel Injector
-Cleaning/Replacing IAC
-Cleaning/Replacing MAF sensor

Any Ideas? I appreciate any help, thanks!

When you say engine at idle is the transmission at N or at D, or you have checked both positions and the "woomp-woomp" stays the same?
1/Fuel and air filters should be changed if they are overdue.
2/Leave the injector for last.
3/Unplug the IAC while the engine is idling at neutral.If the IAC is functioning, then by unplugging it the engine should stall.Cleaning it never hurts, but careful with those tiny gaskets or get some new ones.
4/Cleaning the whole intake and the MAF is a good practice.
Regardless of all the above, a vacuum leak somewhere is still my concern.With the engine idling at Neutral, step hard on the brake for quite a few seconds and see if slowly but gradually the brake pedal hits the floor.It may take more than 5 seconds for this to happen if you have a vacuum leak.
A different check for the crankcase ventilation.While idling take the oil dipstick off and see if there is a change in the idling.
Please keep us informed with your progress.

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SUVord

· #4 · Jan 7, 2011

In the "popcorn" thread you probably noticed the IAC valve was mentioned as well as the DPFE.
After lots of thousands of miles and depending on the quality of the gasoline, the DPFE goes crazy and at low revs it keeps slightly open the EGR valve.With that happenning the IAC gets the wrong signal and thinks that the car is moving, etc.End result is that more fuel than needed is going to the combustion chamber but not enough air and that gulping for air produces this unique sound.That also explains why many of us have noticed a considerable fuel economy when these issues have been fixed.
As for the intake cleaning I have never used seafoam.I know that many in here have used it and are pretty satisfied with it.It simply is not available where I live.
I clean the intake by taking it out and using anything for cleaning it with my favorite method being diesel fuel and a good soap cleaning on top of that.Blow dry it and put it back.

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SUVord

· #9 · Jan 8, 2011

415dispatcher said:
oh and by the way..when i left to go to work tonight...turned the key and it turned over a few more times than usual before it started up.

That symptom may be coincidental to moisture and cold temperatures depending where you live.
A weak battery which is old may also cause this belated start-up.
As for your intake glitches you seem to have different issues to deal with from Robtroma.
An automotive stethoscope would help to distinguish where the strange sound comes from.It saves a lot of hassle and aggravation together with money.

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