V6 abc cabriolet throttle body?

[fourringsrus]

Hi gang, been working on the car this morning and flattened the battery by leaving the ignition on for a while, about half an hour.
Anyway, car back on the ground and jump leads onto other car and hey presto started right up, good, no.
She roared off at about 3000 revs and then dropped off to a rather fast idle, thought aha, throttle body needs to reset or something.
Disconnected the battery for about 5 minutes after it had run for a while and put some charge in.
Re-fitted battery and started her up but now instead of roaring away she fires straight up to 1500 revs and rapidly jumps to just around 1600 revs and returns to 1500 then 1600 then 1500 constantly blipping up and down 1500-1600 about 3-4 times per second.
What do I do about this, whats going on, I have somebody coming to possibly buy the car and this is not very helpful

As a note the work I was carrying out was under the car at the rear sorting out the handbrake cables and mechanism, so not related to anything under the bonnet or electrical, I had the ignition on because the alarm kicks off when armed if you bump around and knock the car.
Soonest response greatly appreciated gang
Many thanks

Stuart

[fourringsrus]

Well after a ton of reading old related threads I tried various re-set procedures which had worked for other members, ie; disconnect battery for 1 hour or two, try ignition on/off for 10 second intervals, pull this, push that, try this ,oh I have forgotten what the hell I was doing, lets start again.
All to no avail, started to think it would need a pro with the right diagnostic kit to have a nose.
Decided to wash and clean the old girl anyway as that always cheers me up,
After washing etc ,I moved the car and the raising/lowering revs had settled, but to around 13-1400 revs steady.
After around 5 minutes it started poncing around again.
Switched off, started up ..........same
Repeat above
And again etc.
After 5-10 times she started up and settled to a 6-700 tickover, sweet as
Took her for a quick run, hit high revs a couple of times and let her rest, switched off, settled for a while, all good
Just tried her again, mid this post, now.....still spot on


So I aint a clue guv, but seems to be sorted, thanks to anybody who has been trying to find something, I'll post back if she goes bad again

Stuart