Joel_CA
Posts: 472
Score: 0 Joined: 9/20/2005 Status: offline
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Pinch the yellow traced vacuum return line at the top of the throttle body- your engine should stumble right away to near stalling before the IAC kicks in to prevent it. If it doesn't, it could be a small number of things with the EGR valve being LAST on the short list of potential problems. Chances are, your engine will stumble pretty good PRIOR to your cleaning, it's just not stumbling fast enough from when the EGR solenoid is activated. The PCM picks this up by way of the Map sensor atop of the intake plenum. Once the EGR is activated under decelleration, it should notice an immediate drop in manifold vacuum. If not- our CEL will turn on. The ported vacuum source (a pinhole sized opening just past the throttle plate) has been known to clog up at times lowering the amount of vaccum available to pull the valve open in a speedy manner. It is located at the start of the blue/green traced vacuum line ontop of the throttle body next to the yellow one i mentioned earlier. Remove the intake hose, open the throttle plate, and clean off the bore with a rag soaked with throttle body cleaner. DO NOT spray directly into the intake. Disconnect your negative battery terminal for a minute to clear the light and check with a specific road test. You'll need to find a boulevard where you can travel between 40 and 50 miles an hour constantly for about 30 seconds. After 30 seconds, take your foot off of the throttle and allow it to coast down to between 5-10 mph. It is important that the throttle is CLOSED throughout this time (the PCM will activate the EGR solenoid and check for that vacuum drop). You may have to repeat this a few times as it will take 2 properly run cycles to trigger that light again (or not). Anyway, that is very likely to be your problem. If not, i have seen other areas that may need attention but we'll get to that later. Joel, CA Diamond Star Technican
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1992 3000GT VR4 & 1996 STEALTH RT/TT #47 *both tastefully modded*
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