So here is my problem. I start the car, instant 1800-2500rpm. Drops to 1500 immediately, then jumps to 1800-2000. At this point the wideband flashes "lean" and the injector pulse width (monitored through MMCD) drops to 0. Then it jumps back to 1800 RPM or so dropping to 1500 RPM , then the wideband shows lean again and the PW is 0. This happens approx 1x a second. When the car is at operating temp the symptoms sometimes go away. When it is not doing this it idles at 1350 90% of the time. 10% of the time it idles at 850. When the AC is on it idles at 850 40% of the time.
Turning on the AC during warm up drops the idle to approx 1400 and (sometimes) stops the surge.
I have checked the ISC, it appears to be a new/reman/not original unit. It ohms out at 40 across each coil (matching the revision spec). The ect ohms out correctly at the correct temperatures, and the connections are good. The FMIA is deleted. I have not performed a BLT test due to lack of equipment, but have checked all the vac lines (all two or three of them....) and snugged up all the charge piping. I have read many of the other posts relating to idle surge, and haven't seen anything matching my symptoms. That of course does not mean there isn't a post. I have also checked the vfaq, and many of the pages relating to idle surge are dead, as is the 1000 answered questions.
I am running a stock auto ecu, 2G Maf in an Injen intake, SAFC II, and stock boost on a 16g. This problem started after I replaced the ECU that was in it with a known good one. The old ECU ran so bad that this problem may have been concealed by it.
Turning on the AC during warm up drops the idle to approx 1400 and (sometimes) stops the surge.
I have checked the ISC, it appears to be a new/reman/not original unit. It ohms out at 40 across each coil (matching the revision spec). The ect ohms out correctly at the correct temperatures, and the connections are good. The FMIA is deleted. I have not performed a BLT test due to lack of equipment, but have checked all the vac lines (all two or three of them....) and snugged up all the charge piping. I have read many of the other posts relating to idle surge, and haven't seen anything matching my symptoms. That of course does not mean there isn't a post. I have also checked the vfaq, and many of the pages relating to idle surge are dead, as is the 1000 answered questions.
I am running a stock auto ecu, 2G Maf in an Injen intake, SAFC II, and stock boost on a 16g. This problem started after I replaced the ECU that was in it with a known good one. The old ECU ran so bad that this problem may have been concealed by it.
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