TPS unstable reading

Previously, I had replaced the TPS due to erratic readings http://honda-eg6.blogspot.com/2011/04/throttle-position-sensor-replacement.html.   

Erratic TPS reading will result in unstable AFR, hesitation at low throttle (jerkiness) and lagging throttle response (kind of like sudden surge forward when throttling in eg. 0% to 5% throttle.)

The same symptoms appear again. The TPS readings were unstable, at times there was no TPS reading until I throttle beyond 7% and my AFR reading was fluctuating during cruising. 

Possible causes that I could think of:

1) Another dead TPS

2) Bad grounding at thermostat (ECU ground)

3) Bad wiring.

After some testing. it turns out to be bad TPS plug, which causes the intermediate readings:

Looking at where the arrow is pointing, u can see that a catch on the right hole is missing compared to the  middle. Therefore, the pin was not held properly in place = bad contact. 

I swapped in one from my spare harness, and tested it. All the above mentioned symptoms are now gone :)


From my understand (after some tuning with Hondata).
The throttle position sensor reading affects quite a few thing.
1) Min. throttle required before VTEC will engage (Not determine only by RPM)
2) Fuel Cut off (ECU will cut off fuel at 0.6% throttle - better fuel economy)
3) Tip-in throttle fuel trim (Extra fuel added during sudden throttle, prevent lean out)