E320 misfire when hot
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Joined: Jul 2003
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E320 misfire when hot
I have a 1995 E320 which has a consistent and annoying problem. The car always starts easily whether cold or hot, but if it's driven to full operating temperature and then parked for over 15 minutes or so and then restarted while hot, the engine runs rough for a couple of minutes before finally smoothing back out. It runs rough under these conditions whether idling or at higher rpms. It feels and acts exactly like vapor lock in older (non fuel-injected) cars. I've replaced the fuel filter and plugs, but I'm not sure what to try next. The car also stumbles a little under full throttle, but this may not be related to the other problem. I have around 80K miles on the car, and the check engine light is not triggered. Any thoughts?
Super Member
Joined: Jun 2003
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From: Middlefield, CT
1994 E320
My '88 260E had a similar problem (though it ran smooth at high RPM and stutterted at idle and acceleration). The distributor cap and rotor were corroded and had to be replaced. Try that out.
Thread Starter
Newbie
Joined: Jul 2003
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Thanks for the idea, but I believe my car doesn't have a distributor. It has the three coils with the waste spark ignition system. If the problem is electrical, then I'm guessing it may be a sensor sending a bad signal (since the problem seems very consistent). I'm inclined to think it's a fuel problem, but I don't want to start messing with things such as the fuel distributor without more info. Any thoughts??
Super Member
Joined: Jun 2003
Posts: 595
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From: Middlefield, CT
1994 E320
Instead of spending big $$$ replacing components with hit ot miss results, have your mechanic hook up the lamdba tester and read the on/off ratio. It can usually give you a good idea as to which component(s) are faulty.
