tomwright Posted April 6, 2019 Share Posted April 6, 2019 Hi guys, below is a link to a quick YouTube video of my 1994 j-spec n/a auto supra which has a problem with a bouncing idle and high revs when put into gear. The car has had a full new ignition system including distributor cap and rotor arm, ignition leads and spark plugs all from Toyota as well as a new battery. I have also swapped ecu’s with my friend but the problem is still the same, I have also replaced and set a new TPS and cleaned my throttle body and IACV. I am going to look at the speed signal wire from the odometer as the tach needle is a bit wobbly and it reads a speed in between mph and kph for instance at an actual 30mph it reads 40mph. I am led to believe a bad speed signal to the ecu can cause high revving and bouncing idle. Does anybody have any ideas off the top of their heads as to what this could be? Any help is much appreciated! Here is the link: https://youtu.be/V-U6F_a2L-c Quote Link to comment Share on other sites More sharing options...
rider Posted April 6, 2019 Share Posted April 6, 2019 I'd probably start with the MAF sensor. Quote Link to comment Share on other sites More sharing options...
evinX Posted April 6, 2019 Share Posted April 6, 2019 Worn throttle body symptoms Quote Link to comment Share on other sites More sharing options...
tomwright Posted April 6, 2019 Author Share Posted April 6, 2019 As far as I’m aware the J-spec n/a’s just have an intake air temp sensor and not a maf, I’ve just had a quick look and this seems to be correct as I can’t find a maf Quote Link to comment Share on other sites More sharing options...
tomwright Posted April 6, 2019 Author Share Posted April 6, 2019 Worn throttle body symptoms As in I should buy a new throttle body or can I fix the one I have? Quote Link to comment Share on other sites More sharing options...
David P Posted April 6, 2019 Share Posted April 6, 2019 GE engine has MAP sensor, not MAF. A worn throttle body won't cause idle difference between P and D. Check that the Throttle Position Sensor is set correctly. Check the closed circuit oil breather system; hose not split and the valve functions correctly. Quote Link to comment Share on other sites More sharing options...
SupraLEDrears Posted April 6, 2019 Share Posted April 6, 2019 Mine started doing this when the ecu was on its way out Quote Link to comment Share on other sites More sharing options...
Dave Posted April 7, 2019 Share Posted April 7, 2019 take the cover off the ECU and have a look maybe a blown cap . Quote Link to comment Share on other sites More sharing options...
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