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Old 01-30-2002, 05:39 PM
Posts: n/a
Rough starting hot and cold

My 88 300 SEL is starting hard and running rough for 30 seconds or so. It runs good after that although get fuel smells. I have adjusted the idle mixture (I know, but the previous owner damage that I am trying to fix) to about 45% duty cycle. It will read ~7v (pins 2 to 3 on test jack) after starting, then gradually drops to 2 volts. Without the engine running and plate in idle position I get 70%. Partial deflection and I get 90%. Full deflection and it stays at 90% duty cycle. The lambda voltage is down to .6v (sensor wire to ground). If I try to adjust lower, it drops to zero. I unplug the throttle valve switch sensor and read the three pins:
1-2 0 ohms (idle)
1-2 0 ohms (full load)
2-3 open ohms (idle)
2-3 open ohms (full load)
2-3 open ohms (partial)

If I adjust the mixture it will start perfect for a couple of times and then gradually return to bad start. I think I have a bad throttle switch. Can these switches be cleaned or renewed vice replace. Where can I get just the throttle switch cable? What else might be wrong with these symtoms?
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