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Roughly a month ago my 2000 Civic EX w/auto transmission had the CEL come on and started having really erratic RPM's and would almost sputter at low speed/slow acceleration, during quick acceleration it had no issues. I had the code pulled, it was P0122(Throttle Position Sensor), bought one on eBay, installed it, unhooked the battery, hooked everything back up, start the car, after 5 seconds, CEL is back on. I drive the car, and the original issues are gone, no erratic RPM's or sputtering. But, now the car isn't shifting properly, it is waiting until 3800 RPM's to shift, doesn't down shift under heavy acceleration(I.e. going uphill). During rapid acceleration the 3800 rpm shift is perfect, but during slow acceleration, it seems like it should be shifting much sooner, 20 mph in 1st gear has the engine screaming. Another issue I have noticed is when I'm slowing down, the car shifts from 2nd to 1st hard, like a thud, it is so hard, it feels like I slammed on the brakes during the downshift. So today I had the CEL code pulled and it's the TPS code again. Does this make sense, what else could it be?

 
Rep Power: 517

You probably need to adjust the new TPS.

While watching your scanner datalist, adjust the TPS so its voltage (at closed throttle) reads 0.49 volts and tighten it down.

You could also backprobe the TPS connector to get the reading on a voltmeter or backprobe at the PCM connector.

Once the TPS reads 0.49v @ CTP, clear codes and give it a drive. See what happens.

HTH

 
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You are speaking Greek to me , how do I adjust the TPS?

 
Rep Power: 517

How did you manage to get it installed?

There is more to the job than simply bolting it on.

 
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Well then I probably installed it wrong, I cut the old screws off since they had the weird head on them, removed the sensor, put the new one on and plugged it in. What was I supposed to do?

 
Rep Power: 517

If you had bought a complete throttle body through Honda it would come with the TPS already installed and adjusted correctly. (Most of their cars.)

You got a bare TPS instead of a complete throttle body, I assume?

The bolt holes in the TPS are oval shaped (slotted) so there is space to rotate the unit for adjustment. Loosen the bolts, rotate the unit to adjust, tighten the bolts.

You need to monitor the TPS output voltage and set it as I already described earlier.


You still have screws holding it on there now, right?

 
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Yes, the tps came with new bolts, I'll adjust it and hope it solves the issue. Do you think the tps, is affecting the shifting?

 
Rep Power: 517

It will definitely affect it.
It is most likely part of your problem, and this adjustment must be resolved first.

If you get it set correctly, you will have your answer.

 
Rep Power: 0

Adjusted the TPS, it fixed the issues, thanks!