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  #1  
Old 12-10-2014, 04:47 PM
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Angry MB 300e Stupid Mode

Hello,
I purchased a 1991 300e 3.0. I helped install a rebuilt trans and new suspension and exhaust. The car runs great for days. BUT every so often I say the car goes into stupid mode. The car starts to run rough and is down on power. The car will not take fuel very well and when you stop and then pull out the car shifts very hard. It may take 3 to 10 miles and then all of a sudden the car is back to normal runs great shifts very smooth. There is no check engine light at all. The car will run fine for days or maybe an hour and will do this again. The car has new plugs, wires, cap. I have checked the plug wires for continuity and they turned out fine. I have looked for lose connections but all looks good. I hope someone out there has seen this problem and can tell me what to look for???? Thanks

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  #2  
Old 12-10-2014, 04:49 PM
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Change fuel filter(s) and report back.
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  #3  
Old 12-10-2014, 08:19 PM
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Stupid Mode

Hello Skippy,
I will be replacing the fuel filter under the car Friday 12/12/14. Is there more than one filter? I only saw the one next to the fuel pump. Thanks
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  #4  
Old 12-10-2014, 08:43 PM
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I think yours only has one, but I'm not sure. I'm more used to dealing with diesels, which tend to have two or even three.
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Whoever said there's nothing more expensive than a cheap Mercedes never had a cheap Jaguar.

83 300D Turbo with manual conversion, early W126 vented front rotors and H4 headlights 367,xxx miles
08 Triumph Street Triple 30,xxx miles, lowered 10mm in front, Pirelli Angel GT tires, EBC HH brake pads, otherwise stock.
88 Jaguar XJS V12 93,xxx miles. I should be in the garage now.
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  #5  
Old 12-10-2014, 11:23 PM
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Check the hose under your fuel distributor ... its in the lower center and comes toward the bumper. There are also 2 vacuum connection under it... on the far right as you stand in front of the car. I believe you can check them with a mirror.
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  #6  
Old 12-11-2014, 06:44 AM
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check all vacuum,and hoses from crankcase to.I changed my fuel pump,at 165,000 miles to be safe.
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Old 12-11-2014, 06:54 AM
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The hard shift is a hint that there is low vacuum at the tranny vacuum modulator. Check it, and the lines and fittings going to it.
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Old 12-11-2014, 03:29 PM
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Quote:
Originally Posted by Hirnbeiss View Post
The hard shift is a hint that there is low vacuum at the tranny vacuum modulator. Check it, and the lines and fittings going to it.
The low vacuum is just a symptom of the problem. Intermittant problems are almost always electrical. A clogged fuel filter cant "clear" and then "clog" again. Think about it.


Park the car, start it, hook up your voltmeter to check duty cycle and wait. Observe what happens when it starts to stumble and let us know what your readings were.

I had a similar issue, and I had to drive around for a week with my voltage tester riding shotgun. Once the stumble started, I pulled over and checked. Ended up being a loose ground.
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  #9  
Old 12-11-2014, 04:38 PM
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Sounds like you may have a misfire. Slow to rev up during a misfire can cause the trans to shift hard, making it seem as though it may be a vacuum issue....See this all the time. Check your cap, rotor, plugs, and plug wires....Just a thought. oops, didn't see that you already addressed the ignition parts. Could also be a missfire from a bad fuel delivery.

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