Was chasing a possible throttle body/TPS fault - problem solved??

[carcollector]

I've got a 2006 V6 WM Caprice with quite a few KM on it. Every now and then it would throw up a code - either PO 121 or PO 221 - both are to do with throttle position sensor readings that are out of range. This didn't really affect the driveability of the car, except that it went into safety mode and limited power, etc. Along with that, on very light throttle and mostly when cold, the auto trans used to hunt around for gears, eg straight flat road, constant throttle, it would run up and down a few hundred revs every now and then, and change from 5th to 4th. This never used to throw a code though.

It used to be a chauffeur car, so I thought that it probably would have spent a fair bit of time cruising, and on very light throttle - maybe it had an intermittent contact on the throttle body sensor just above idle, through wear and tear?? I priced a genuine Holden throttle bodyand TPS unit - $470. I rang the local (SA) Commodore wreckers - Just @@@@odore spares, and was told that a second hand 'stock' V6 throttle body was $195, but the 'high output' throttle body was $270. Then I saw one on EBAY - brand new, genuine Holden, part number 12615503. I checked again with Holden, and apparently the early V6s had two different throttle bodies, but they had both been superceded by a new one - part number 12615503. I bought the one off Ebay for not much more that the Holden wrecker wanted for a second hand one, fitted it, and so far, it has appeared to fix both problems. No more error codes, and no more transmission hunting.

Fingers crossed, but all looks good so far.

Oh, and it's easy to fit too. The hardest part is removing the plastic air inlet runner.

[carcollector]

Update on this. No more error codes, and no more transmission 'hunting' on light throttle since the new throttle body and TPS unit has been installed. When I get time, I'll strip down the old throttle body and TPS, and see if anything's worn, or obviously wrong.