Draklia
Well-Known Member
So, million$ question. You mention your tuner. Has it always done this on the tune that’s on the car? Does it run right when it’s on the factory tune? Might just need some work done on the tune.
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ugstang17
Well-Known Member
The car has aftermarket LT's on it. The O2's are further down stream so tuning has to be done to take this into account verses the factory location. The factory tune would not likely run on this setup in this case. It;s not to say that weather conditions may have caused this, but since the OP never indicated this when I asked I conclude then that nothing weather wise has drastically changed which could account for a tune related problem. I prefer to troubleshoot and eliminate more likely faults before jumping on the tune wagon. Tuners tend to react better in trying to help if you have first eliminated the possible faults before just calling them to ask for assistance. You will get a lot more from them using this approach both in assistance and in respect.
acm543
Member
- Thread starter
- #19
I may have got it. As ugstang17 said, pull off the throttle body and clean it really well. I put it back on and started the car. It started up and once the RPM’s dropped they didn’t fluctuate and lambda 1/2 didn’t fluctuate either. Soo hopefully that’s it. I’ll check again in the morning.
ugstang17
Well-Known Member
Good job. Time is the tell tail on a fix. If it returns check the PM I sent and continue where you left off. Often times carbon build up on the back side of the TB can catch the flap just enough to cause it to oscillate slightly over shooting. A relearn may have to take place for everything to be happy but that will take a few days of driving, or following a TB relearn procedure which should be in the owners manual in the glove box. I've never had to do it, I just drive the car for a while and any oddity seems to clear up. Keep us all posted.
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ugstang17
Well-Known Member
Possible the car has to relearn. So you may wish to perform that after cleaning the TB. Usually in my experience a good drive reteaches everything. I've never had to do it personally after cleaning a TB but someone on here as likely posted the procedure or its on youtube. Otherwise you are back to following the common checks I could think of. Good luck. I don't have schematics to give you or reference for the15+ S550. Sure would be nice of you to share what is found after you resolve it. I still lean toward a wiring harness, or O2 extension. Possibly both O2's but the probability of two going out at the same time is remote. Good luck.
Grim12
Well-Known Member
Good info.
Getting a P2251 myself. Did you replace them yourself? Can you tell me the part number? Going to try and replace the sensor myself, but I've never done it before
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acm543
Member
- Thread starter
- #26
No I didn’t do it my self. I had the shop do it, because I wanted to make sure there weren’t any other probleMs causing the O2’s to go bad. It shouldn’t be too hard at all. Just take the original O2 out and put the new one in. If you have LTH it will be even easier. From what I read you’ll want penetrating fluid for sure. There’s tons of YouTube videos on it. I don’t have the part number sorry. I’m sure you could call ford and get it or even look it up online pretty easily.
