98 v70 base - rpm drop in idle

[jdpooley]

Been driving my car for years with the same niggling issue. There have been posts on here about this before. I think it drove JRL about crazy on one vehicle. I just live with it having replaced a bunch of stuff (unrelated to it) including an engine, and not having it go away. The only things I haven't replaced are crank position sensor and throttle position sensor, as well as air idle control valve, coil and fuel injectors. I have also not checked the alternator. Anything else, plugs, cap, rotor, vacuum, pcv, plug wires, etc. I've gone over and/or replaced. They have not managed to alleviate the issue. Never threw any codes as a result of this shake either. I have cleaned the throttle body numerous times and replaced the MAF as well as ECT and thermostat (all unrelated to diagnosing/treating this issue) to no avail. It is just annoying. I live with it.

I just bought a '99 v70 with 120,000. My car does the same when slowing to a stop. Very annoying.

[bncme262]

at idle the idle air controller: iac (a stepper motor that moves to open a port allowing air to bypass the closed throttle plate) should control the idle, if the iac is lazy or internally clogged that could be the issue. there should be no vacuum leaks. i do recommend cleaning the throttle body and maf sensors thoroughly with the appropriate chemicals. my idle acted funny just before car died due to a dead fuel pump as told to me by wcs in rockland, ma (wally owner and scott parts are superb).. to prevent dead f/p i should have changed the fuel filter. pull s/p wire plastic cover and check for arcing at night and look inside dist cap: clean contact and carbon arcing. hope this helps.

[nkdwpn40]

Hey. Its the ect. Mine only does it when I don't let the turbo cool down. I think the turbo heats the system over board and tricks the ect in to thinking its hotter than usual at start up!

[rmmagow]

ECT and Thermostat fixed this issue on my v70 LPT.