4agte idle problems

[cri_ag]

hi all, im having problems with my 4agte. after the last event at oran park, my car has decided to fluctuate revs at idle from 1500 to 2300rpm constantly. i have tryed a spare throttle body to no avail. weird part is when i pull off one of the vacuum lines (any one) and create a vacuum leak, the idle goes down as opposed to the usual raise in idle. any one have any ideas why this might be so?

[Cuzzo]

Generally the hunting idle is to do with your water temp sensor or air in your water system giving the sensor a false reading.

[cri_ag]

ya that was on the list of things to check when i find the cable that plugs my laptop into the computer!

[JP]

unplug your TPS while the engines running. If the hunt stops you need to adjust the TPS.

[Ben Wilson]

Are you using a ZE ECU? It sounds a lot like the problems I had with my ZE, a new oxygen sensor sorted it out nicely,

[cri_ag]

I'll try the tps tonight, I'm running a haltech so no oxygen sensor involved. Cheers

[JP]

ahh, if it's a haltech then it is not likely to be the TPS. On a factory ze or ge ecu when the TPS is set wrong (IDL switch not engaged at idle), the ECU can hit the "fuel cut RPM" and then you get a bouncing idle

[cri_ag]

problem found, massive crack across the bottom of the manifold, bleeding air in.