poor idle and cruise control not working

[advdisco1]

Hi, can anybody help i have a 98 d1 v8 idle sometimes gets stuck then slowly comes down to normal then other times it goes below idle then up and down eventually stalling. i clean out the part on the back of pleunem chamber and changed tps but stiil didn't fix it.

cruise control was turning itself off but now doesn't work. i change hoses( small cracks) and changed vac pump but still not working.

have you had this problem before if so what was the cure. thanks.

[matt_w]

could the injectors be mucking up or air flow meter

[armbrup]

You have 2 separate problems.
1 erratic idle is the stepper motor. perhaps it needs replacing but maybe clean it again. You should also clean out the throttle body wher ethe oil breather inlet is and the blade itself.
2 No idea on the cruise. In my aftermarket Command 350, this problem is caused by the solonoids in the vacuum actuator failing.
Regards Philip A

[advdisco1]

yeah thanks but ive already changed the af meter and ive cleaned the flap, intake and stepper motor (they didnt seem that dirty).
got a price today for the stepper motor $174. wow small part.

[mickrangie]

i had a similar problem a while back it turned out the vac hose that runs off the cruse diaphragm was kinked and it was holding the the throttle open via the vac pipe on the cruse and see if it still happens. with the stepper motor give it a bath in crc or the like and see if it comes to life if it was the problem.

HTH

Mick

[little rusty]

a mate of mine and i have had this issue with our discos and i would say the stepper motor is the biggest culprit. I have replaced all ignition components except the dizzy and the amplifyer off the coil. no dramas since i cleaned out the stepper motor. mates just goes crazy sometimes and holds at 2000rpm...

i would avoid the AFM until you have ruled out all other options as they aren;t cheap and second hand is propably not the best. find one without idle troubles and swap the meters around to see if there is a difference. also, spraying solvents to 'clean' the afm will only make it worse as the metering wires hate it! apparently - was told this by ecu tuner on the dyno at Northside 4x4

$174 new stepper motor? provide details as we have been quoted $300 + for new ones

[firey69]

to test the stepper unplugit start the car plug it it should change your idle if not chances are its buggered

[advdisco1]

karcraft in silverwater sydney was $174(out of stock til 20/7), tr spares $190(in stock) used to be just under $300 but they have drop in price.
tried 2 second hand ones with simular issues. i think i'll try soaking my original one for a couple of days, if it doesn't work i'll buy a new one.