06 TSX Surging

My '06 TSX with just over 88K miles has started surging in the past week or so. It is most noticeable when accelerating, but also happens when maintaining a constant speed. The engine RPM will vary +/- 100 RPM. The
check engine light is not illuminated. I am, and have always used 92/93 octane gas. I have gone through about 1.5 tanks of gas in the past 10 days or so. Fuel economy has dropped at least 2 MPG in combined driving.
The only other thing unusual is that I've had to re-pair my cell phone with the vehicle twice in the past 2 weeks. I'd click on the hands-free talk button, tell it who to call, and it would respond with "No Phone Found".
Thanks for any advice,
Bob
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snipped-for-privacy@yahoo.com says...

Took it to my local mechanic. They spent an hour trying to find something. They were able to get a single mis-fire on cylinder #2 when a dump truck pulled out in front of them and they quickly lifted off the gas. They verified that the fly-by-wire throttle position sensor and throttle body valve were in sync. Throttle body was very dirty, so they cleaned it. It seems better. Their suggestion is to drive it until it becomes consistent enough that the computer logs a code. I'm due for the 100k mile maintenance in about 12k miles, so I'll make sure the plugs get changed then.
Bob
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Bob,
I own a 2006 TSX with a 6 speed manual that currently has 117,000 (mainly highway) miles on it. I had the same issue with my TSX at 70,000 miles. At first I thought it was my imagination, but finally I realized that it was not. I did 3 things: 1) I changed the plugs, 2) I switch from Citgo premium to Exxon premium, and 3) I added a can of BG. After about 3 weeks, the surge went away. It eventually came back, after several thousand miles, so I added another can of BG, and once again, it went away. Now at 117,000 miles, it is back. Needless to say, I will be adding another can of BG soon. I also discovered that during a cold start, it is much more notable. I have a 50 mile commute (one way), and when I get to work, and put it in 1st gear at 3,000 rpm's, it is much less noticeable, almost like it is not there. After the TSX sits all day at work, once again, it is much more nocicable. I hope this helps.
Tony
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Not sure what you mean by surging, but my first guess is your idle air control needs some attention.
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snipped-for-privacy@nastydesigns.com says...

In my case, with the automatic, there are two common situations; 1) Under light throttle the car will surge forward for less than a second, then slow down, and repeat. 2) I pull out of a parking lot with a slight slope towards the street and make a turn into the traffic lane. I give the car a bit of gas to get it rolling, take my foot off the gas, and as I'm part way into my turn into the traffic lane, I give it some gas to start accelerating and it stumbles as if the fuel got cut off for a fraction of a second.
I never seem to experience this with cruise control engaged. This makes me wonder if it's a problem with the TPS or whatever converts the mechanical throttle movement to digital signals for the engine control computer.
I wonder if I might have a fuel filter problem, but I've never run the fuel tank empty and 99% of the time, fill the tank before the low fuel light is illuminated.
The Check Engine light is NOT illuminated and my mechanic says there are no stored error codes.
Bob
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065b0505594b06f549b8b6640ba408f1 snipped-for-privacy@example.com says...

Tony,
Thanks for the reply. I'm now at about 90K miles. I probably should go ahead and change the plugs.
Bob
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snipped-for-privacy@yahoo.com says...

I took the TSX to the dealership today. As expected, there was no code to be read from the OBD port. They drove the vehicle and observed the problem. They suggested replacing the APP(?), or what I would call the throttle position sensor. I agreed since I never seemed to have the problem with the cruise control engaged. After replacing it, they test drove it and said it was much better. I returned their loaner TL, paid the bill, and drove off with the car behaving they way it should. The bill says they replaced 37971-RBB-003: Sensor Assy. Total cost was ~$325.
Bob
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