92 Volvo 940 est fast idle speed

Hi all,

At my wits end! The idle speed on my 940 will not drop below 1100
rpm. Have tried all the usual stuff, changed IAC, TPS , ECT,,and
carried all the adjustments out as per the manual and the tickover
speed still doesn,t drop to the magic 750 as required! When driving up
to lights or whatever it will drop to @ 1400 and when you take your
foot off the brake then it will drop again to @ 1100. Occasionally but
very rarely, it does stay at 750 and then when you drive off and stop
again its back at 1100. Its got the Bosch LH 4 injection by the way! If
anyone can help I will be eternally grateful to them!! HELP !

 

That's LH 2.4 if you don't mind!! You have a couple of alternatives here,
check the throttle cable for smooth action and roling on/off the drum on the
throttle quadrant. Then thoroughly clean and inspect the inlet tract (air
filter to throttle block) and any wiring to components. After that reset
throttle switch and settings.

All the best, Peter.

700/900/90 Register Keeper,
Volvo Owners Club (UK).