Contour Enthusiasts Group Archives Forums General Troubleshooting Idle problems Please HELP!!!! I'm pulling my hair out!!!

Well, I have tried all I can think of here, and I am still at a loss. I will give all of the symptoms and see if anyone can help me out here. I have done a search here and seem to see a lot of people who have had a similar problem being solved by cleaning the MAF, but I have cleaned the MAF and I get no faulty reading from it.
SO here goes.
A few weeks ago, I started feeling like my car was getting a bit sluggish. It seemed to have a bit of a knock at acceleration as well. My car has 70k miles on it. So I replace the spark plugs, they are a bit gunked up to say the least. So after I do this and run a fuel system cleaner through it, it drives great has restored pep, etc. For about 25 miles. Then I get a CEL. After this it seems like it is idling a little rough. I put in premium gas, and drive about 100 miles and this rough, stumbling idle becomes more like a barely stays running. It is going down hill fast here. It also hesitates off of idle at stops. Sometimes bucks a little, or needs to think about if it really wants to go or not. After I get past initial start off of idle, it runs great, has power etc. It sounds like it may be having a little back fire or something off of idle too when I floor it to accelerate. Though it is not as LOUD as a backfire, more like a pop or a crack, loud enough to hear, not loud enough to get people hitting the deck thinking I am firing at them.
So I get my trusty OBD2 scanner and see an error 171. Check into it more and my O2 sensor #2 is not responding. I buy both before store closes and replace the one not responding. The other one seems ok, so I want to return the one I don?t need, they are costly. I have cleaned the MAF and replaced the fuel filter, and cleaned the entire air intake system, though it looked clean enough to eat off of. I have driven it and idled it about 10 miles. And it is STILL behaving badly though my CEL has not come back on yet. It has died at idle a couple times now as well. All of my hoses are in good shape too. Checked for vacuum leaks and I do not believe I have any. When it is in park it idles fine too, it only behaves badly when in drive with the brake on.
Now I have no codes aside from what I am told is a normal reading of .95V on my throttle position sensor. It says it is always at 18%. Then when I step on it, seems to jump up to 50% before going up and down smoothly. I had 2 mechanics tell me this is normal. I am a little baffled since I plugged the OBD2 scanner into my boyfriend?s and my brother?s girlfriend?s cars and their TPS?s read at 0% at idle and rise smoothly, they however have ?96 import cars (VW and Nissan) with standard transmissions and my ?97 Contour is an automatic. It has a Zetec engine. I called Ford and a dealer about the MAF sensor recall problem and they tell me based on my VIN, my car has no problems I have had all recalls and Service bul?s fixed. We?ll see IF I can ever log into their site, I?ll like to check this myself.
Does anyone have any insight on this problem, besides telling me to clean the MAF?
Thank you so much.

It sounds like, before the oxygen sensor change, it was running very rich. It might still be running kind of rich, or you might have a different problem now. I would have replaced both oxygen sensors. Lack of a blatant trouble code doesn't necessarily mean it's good as new (though they say you can sometimes restore an old one just by heating it with a blowtorch).

I'd take a fresh look at the plugs and see if they're still dark and gunky.

I don't trust that your throttle position sensor is okay. That doesn't sound normal to me. I haven't voltmetered my own (though I've been meaning to lately, for reasons I won't go into here). Try taking it off and squirting it with some cleaner and see if it reads smoother, I guess.

plug your maf back in?

Hi,

In your dissertation, , I didn't see any mention of the EGR (exhaust gas recirculation)valve or the IAC (idle air control) valve. (Sorry if you didn't need those definitions...you do seem rather well versed). You might want to investigate a possible stuck EGR (although that should throw a code, it might take a few driving cycles for it to show up) Most manuals say to look for gunk aroung the "pintle shaft", the little rod inside that has the little "button valve" attached. As far as the IAC, it operates a valve similarily only with a solenoid controlled vacuum regulator thingamabob dumerflotchie....not too versed on that piece. .
When you state, "clean enough to eat off of", do you mean the intake manifold was removed and inner passage ways and runners degunked (which would be the most thorough method of cleaning) or was that to mean the exterior is clean?
When you put in "premium" gas I believe most "techs" will tell you that can exacerbate any pre-existing flaw, due to a slightly increased demand on the ignition system to ignite it. I believe these cars already idle on an extremely lean mixture and may, when coupled with the premium gas and an additional slight air leak, cause or contribute to, the rough idle condition. When the vehicle is put in "drive", the PCM increases the injector duty cycle (more fuel) a bit and may explain why it idles OK in "drive".
Lastly, were the spark plug gaps checked before installation? Sometimes they can get knocked around in the box. Some people just put them in without checking and this usually works fine however there's always Murphy's Law to consider. Spark plug wires, were they ohmed out? I think they're supposed to be around 8K/ft.

There, I just swung as hard as I can...hope someone helps you out...Ed

Edorfox, thank you for all of your tips. I have checked most valves/sensors. I was referring to the interior of the air intake as far as looking clean enough to eat off of. I did spray solvent onto the MAF just to be sure, but everything looked good. I will try using the regular gas again, I had started using the premium because of the knock it was giving when accelerating. The plugs were gapped but I have not gone through the EGR, but I did look at the IAC and I targeted everything pretty specifically with the OBD2 Scanner. I have not run it through 12 drive cycles since resetting the computer, so my next step as suggested by someone at a dealership I spoke with is to try just driving it through 12 drive cycles and see if it auto corrects itself. Seems far-fetched, but he swore the computer in this car does that, and he described exactly what my car is doing. We'll see I guess. Otherwise I'm right there with checking the EGR. Oh, BTW, it idles well in PARK. It is when it is in DRIVE that it barely stays running/dies.
Thank you everyone for your suggestions, I'll be sure to let people know if the 12 drive cycles really does a blessed thing I'm crossing my fingers.

I just tuned up 3 Fords this month that all had similar running conditions as yours All around the same mileage. They (Many Fords) always seem to lose a plug wire around 60-90k in my experience. This includes my Contour. It was around 65k or so that I had one go bad on it. It seems to, most the time, be the longer of the plug wires that tend to fail. Just a thought though. Check for a dead hole on one cylinder. My Contour started just doing it intermittent at first, and then progressed to a constant miss. This causes havic with O2 sensor readings, as raw gas from the unfiring cylinder is just dumping out the exhaust, which is telling the computer that your too rich, in turn making the computer switch it to extreme lean to counteract it. That will also cause the O2 sensor to stop switching, as it just wants to stay on full lean (since it can't get lean enough). I'd check plug wires before persuing deep $hit.

My plug wires went bad at 50K, and the symptoms were quite different from this. For one thing, misfiring causes the CEL to blink, and that's not something you fail to notice.