2005 civic lx auto- bought 3 mos ago, no warrantee- here's the whole story in case it helps:

1 month ago car unable to accelerate after stopping at red light with a noise as if I am pressing gas with it in park, yellow malfunction lamp comes on. As manual said, gas cap WAS loose- then car drives fine and light goes off after 3 trips.

Few weeks later same light and weird driving, gas cap may have been loose- didn’t feel like it- but then car drives fine and light goes off after 3 trips.


Few days later- light on and weird driving but gas cap is NOT loose and light doesn’t go out. Car can drive at higher speeds but cannot accelerate after I slow down a lot or stop. Have to restart car at every red light to get it to accelerate a little better. Mechanic pulls a p0122 code (tps malfunction and may be an intermittent problem) but he says cannot replace only the tps, need whole throttle body. Resets the code so light goes out and drives ok, but light comes on 3 trips later, again just after accelerating. Mech resets it again and its ok- but seems to lurch forward as if I’m slamming on the brakes while at low speeds or coming to a rolling stop. Accelerating very slowly seems to keep the light out and car driveable for this week.

Looking online- people say TB can be cleaned, mechanic says no, Honda says yes. Other say wiring problem, mech said “wires looked ok” Honda says maybe. Both say maybe to the TB replacement.

Honda charges $120 for diagnostic, which they say may or may not lead them to the definite solution. Labor $109/hr. TB itself is $350 through Honda which they say I should not get anywhere else. Mech said code says computer may have to be reset so he didn’t think he could do it. But honda says anyone can replace it and comp doesn’t have to be reset.


Bottom line and questions-------who should I believe? Everyone says the TB itself rarely has to be replaced. In the interest of being poor not getting ripped off, should I skip the diagnostic and just get the TB part and have my mech do it? Can I get it anywhere but Honda? Should I get the honda diagnostic in case its just dirty or worse, wiring problem that my mech doesn’t see? Is cleaning even possible or a culprit of the symptoms described? Did having a loose gas cap too often break the Tps?

Has anyone had the same problems described and what was the solution?

Thanks I am a clueless chic if you haven’t figured it out, with no smart men around who know **** about cars!

 

First off, when you describe the acceleration problem, you say it's like pressing the gas while in park. Pressing the gas in park just revs the engine, just like in neutral. Are you saying that as you give it gas, the RPM goes up but the car doesn't move? I would think you mean that it's driving like the parking brake is on, with very little power and that the engine bogs down when you floor it. Now, the code you're getting pops up when the TPS signal is too low. If this is caused by the reference voltage (5v power wire to the TPS) being too low, then replacing the TPS and/or TB won't help anything. The TPS needs to be checked and set with the motor not running. Intermittent engine problems usually occur when the motor is running and therefore you may not be able to actually observe the low voltage problem with the TPS. You should probably check the voltages yourself before replacing anything. Get a meter and set it to 12v. Wedge the black probe into the battery negative post. With the motor off and the key in the ON position, use the red probe to stab through the sheath of each wire coming from the TPS and write down the readings. The signal output wire (i believe it's red/something) should read about 0.4v. While checking the signal wire, manually open the throttle all of the way and write down the value listed on the meter. The voltage should rise smoothly as you open the throttle. There are places you can get a TPS without the TB but it's not reccomended by Honda. If you know someone with your same engine, you can borrow their TPS for just a few minutes to see if replacing yours fixes the problem. If you replace the TPS, make sure the little plastic arm under the TPS fits properly into the little slot in the TB.