

| Subject: | RPM oscillations when cold |
| Date: | Thu, 13 Jun 1996 07:23:00 -0400 (EDT) |
Hello, Whenever I start my 87 vanagon, and the engine is cold, the idle will oscillate from about 600 to 850 RPM and is rough. This morning when I started it, I pressed lightly on the accelerator to increase the RPM to about 1400-1500 range and then held it steady. The RPM would then oscillate from 1400-1500 down to 950-1000 and then back up. When it swings thru 950-1000 it is also somewhat rough. I didn't time the period, but it was regular. After I pulled out and set off to work, but before the engine completely warmed up, it runs very rough. Hesitates when I accelerate from a stop, then charges. When in 2nd/3rd cruising thru the development at 25-35 mph the engine is not responsive to gas pedal inputs. When I got to work, a 15 minute drive, the engine was warm: temp needle centered in the gauge. The idle was stable at about 750-775. I know this is lower than the Bentley manual says it should be, but it was stable. Then I repeated the increased steady RPM. Accelerated the engine to 1400 rpm and no oscillations. Hmmm. What is it that would cause the idle to oscillate so when the engine is cold? If anybody on the list is an VW/digifant EFI guru, I'd really appreciate any advice about trouble shooting this anomaly. Thanks, Fred Porter porter_fred%pax9@mr.nawcad.navy.mil relax and spin 87 syncro
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