04 Ford Escape misfire?

[wander2039]

Had this problem with our 04 Escape for a while now (2 years 10+k) and I think it's finally getting worse. At idle in either park or neutral has a looping idle, never happens above idle. Will vary from normal idle up to 1k maybe more. Has a distinct popping noise coming from the intake. No codes right now. Did have one (can't remember the code) that dealt with the EVAP system detecting to much air flow. I put some MMO on the gas cap seal and it's been off for about a month.

Sparks plugs have around 40k, all filters are new. I'd pay for a code right now! On a recent trip averaged 23.5 and seems to run fine otherwise with plenty of power. The power steering did have a leak but that's been fixed. Some have pointed towards the MAF, IAC or few other sensors. All sensors are factory. I did replace all the vacuum lines under the hood. Any ideas?

 

[toneydoc]

I had a similar problem in my 94 Jeep recently. It did the same as yours for a while. Then it started misfiring badly. I checked the coil to distibutor and distibutor to plugs and had some corrosion in two places. I replace plugs, spark plug wire set and distibutor cap and it is running fine now. I would check the plugs and wires for any corrosion.

 

[wander2039]

Has COP's... I have checked the connections on all 6. Should get a CEL if its one of those though.

 

[bdcardinal]

When the spark plugs were replaced, were the intake o-rings replaced as well?

 

[OVERKILL]

Originally Posted By: Eric Smith
Has COP's... I have checked the connections on all 6. Should get a CEL if its one of those though.


No, you won't. I had a misfire under load on the Expedition, never threw a CEL. Apparently Ford's OBD2 logic requires an INSANE number of misfires before it triggers the CEL.

If you know somebody who can read the proprietary Ford data you'll be easily able to see which COP is likely at fault. That was the case with mine. There were something like 400 misfires for cylinder #8.

 

[bdcardinal]

The nice thing about the IDS is you can do coil stress tests, injector flow tests, power balance and relative compression tests without opening the hood. I bet there is something there that a regular scan tool will not be able to find.

 

[wander2039]

The intake gaskets were replaced. Might just break down and take it to the dealer. Would be the second time in 6 years and almost 100k and that was just a recall.

 

[mechtech2]

Coils, plugs, etc usually show more failure under a load, not idle.

Popping out of the intake sounds like a bad valve/seat, or a sticky valve/lifter.

 

[The_Eric]

Originally Posted By: Eric Smith
I did replace all the vacuum lines under the hood. Any ideas?


Even those large vacuum elbows and hoses in the breather and PCV system? Fords of that vintage liked to collapse and split.

 

[mattd]

ford misfire logic is stupid. i was working on a van with a DEAD miss at idle. would not set a code. try to find a scan tool with software for live cylinder contribution/power balance test.

 

[wander2039]

Just a quick update.. Took the cover off underneath and took some brake cleaner to the crank and cam sensors and also another I think for the alternator. Then took the water hose and hosed everything down good. Really acted up upon startup.. Worse than before. But when it got hot it stopped and so far the idle has been rock solid after initial startup, it does hunt a bit at startup but evens out in a few seconds. Not holding my breath seems like to easy of a fix.