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-   -   Sputtering at Idle loss of low end power (http://www.focusfanatics.com/forum/showthread.php?t=299260)

AliasJerk 10-07-2012 05:35 PM

Sputtering at Idle loss of low end power
 
Just started running into this problem about a month and a half ago. I was driving in a torrential downpour, CEL flipped on so I pulled off of the e-way and noticed the idle was a bit "lop sided" best I can say is it sounded kind of like it was "cammed." when I went to take off from a stop the motor hesitated a little bit for about 2 seconds then would take right off no problem. This would only happen probably once or twice in a half hour long drive, and more prominently when I would hot start the motor. Like if I went into a store and came back out a couple of minutes later.

The CEL pulled a code for an O2 sensor, although I accidentally threw the piece of paper with the code number on it away [?|]

Resetting the computer resolved this issue and I drove it for about a solid month before it came back again, I was in a rush, had a bunch of places to be so I reset the computer again and kept driving, but same symptoms; lop sided idle, hesitating at take off, etc.

Today, the CEL remains off and has for the past 400 miles since the last reset, but while cruising at about 30 mph, motor at about 1800 rpm it started to sputter and buck. Pushing the accelerator pedal down a little bit resolved this and it stopped again.

I have never had an O2 sensor fail on me, but given thats the code it gave me last time, would this be the correct symptoms for a failing O2 sensor?

whynotthinkwhynot 10-07-2012 06:11 PM

O2 sensor codes can indicate other problems depending on what the code was. Typically the sensors themselves last about 100k miles, but there's no sense in replacing it if it's not the actual cause of the problem.

Check your air intake for leaks and your vacuum lines first.

Your symptoms could be a sign of a sluggish TPS, but let's wait on that one since it won't throw a code indicating it's bad- it never will, so it's sort of process of elimination for that one.

Try tune-up items first. You should also pull the plugs, clean, re-gap, and reinstall. I'd replace the wires if you have lifetime warranty wires- if not, forget it for now. Fuel filter, air filter, clean the MAF, and that should be about it. That might solve all your problems.

AliasJerk 10-07-2012 07:59 PM

Spark plugs are newer, I did them last year, the car just passed 100k. Has a brand new air filter. I pulled the fuel filter last week and as far as I could tell it was original, covered in corrosion, still had motor craft part number on it. Cut it in half to find it was plugged with rust and dirt. At the same time I ran seafoam through the gas tank. Plug wires are original, but it doesn't feel like a misfire. It feels like the car falls flat on its face for a second then takes right off. I could try cleaning the maf, what's the best chemical to use for that?

whynotthinkwhynot 10-07-2012 10:08 PM

MAF spray cleaner. That's probably not it though.

For intermittent problems like this I like for people to go with a tune-up first. Sometimes that solves the problem. Since your first issue was caused during a rain, you might be looking at a cracked coil. Bad coils will cause HO2S codes like "running rich".


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