I've searched the previous threads for hours without finding the solution to my problem. My '90 300TE-24v (104 engine without emission control equipment) starts fine when cold, settling down from 1200 rpm to its normal 600 rpm within a minute or two. When warmed up however, it starts fine but the idle speed hunts up & down between about 400rpm and 1500 rpm, gradually settling down to 600 rpm in about 15-30 seconds. Sometimes it drops so low it stalls and has to be restarted a couple of times.
At all other times it runs fine.
I have changed the OVP relay & idle control valve to no effect.
Any suggestions?
TIA
Adrian

__________________
90 300TE 24v (M104 eng) 207K miles
87 300TE (M103 eng) 269K miles (and never had the head off!)
86 300TE (M103 eng) 230K+ miles (donor car)
95 Toyota Lucida diesel 4wd
86 200T 165K miles (sold)