Date: Sun, 18 Apr 1999 12:56:07 -0500 From: "Benton Quest" <campjohnnopsamhio.net> Subject: Intermittant lean out
I have a vexing problem with a 1986 SAAB 900, 8 valve, base model. Every once in a while, usually the second start of the day, or when just cruising along, with no warning, instantly, the car goes lean, and power drops way off. It can come back to normal instantly, so I think it is an electrical problem. It only does this about 5% of the time, not enough of a bother to take it in, but I have lived with this for 15 months. Sometimes the tach will drop dead when this happens, and sometimes the tach drops dead and the car will not lean out. The tach has a mind of its own, sometimes working fine, sometimes dead. Sometimes the tach will turn on/off with the turn signal, but not always. In this lean condition, the car will respond to revs and WOT, but it is hard to get rolling from a stop. It is not a fuel pump issue. I hot wired the pump so I can turn it on from the dash. I believe the ECU is getting a bad sensor signal and telling the regulator to lean out. It may be the ignition pulse amplifier. But this condition is only occasional and instant. It is really weird.
