1997 E420 Multiple Missfires
Thread Starter
Newbie
Joined: Jul 2010
Posts: 5
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From: Virginia
1997 E420, 1990 560 SEL, 1998 CLK 320
1997 E420 Multiple Missfires
Mt 1997 E420 is running poorly, rough and loss of power, also poor fuel millage and the smell of raw fuel in the exhaust. I started having these problems at 154K so I had the 150K work done at an indy. Plugs, boots, and all 4 O2 sensors replaced.
I am at 168K now and all problems have returned. Codes show cylinder 2,3, and 8 missfire, multiple missfires, and rear back O2 sensor failure.
I I found all this returning odd but I did use an indy I had never used before, generally I do all my own work after warrenty but got lazzy. So I pulled and replaced all plugs (copper ones spaced correctly now) the indy had installed platnum plugs in an amazing aray of poor gap settings. I also replaced the 3 boots. The O2 sensor erros I figured was just do to raw fual because of the missfires so I have not replaced it yet.
Unfortunatly this didn't correct anything so I went ahead and replaced all 3 ignition coils. This also has not solved anything. I can't see an O2 sensor causing all this and while I didn't get a code for it this seams to me the next thing to replace is the MAF. Ideas?
I am at 168K now and all problems have returned. Codes show cylinder 2,3, and 8 missfire, multiple missfires, and rear back O2 sensor failure.
I I found all this returning odd but I did use an indy I had never used before, generally I do all my own work after warrenty but got lazzy. So I pulled and replaced all plugs (copper ones spaced correctly now) the indy had installed platnum plugs in an amazing aray of poor gap settings. I also replaced the 3 boots. The O2 sensor erros I figured was just do to raw fual because of the missfires so I have not replaced it yet.
Unfortunatly this didn't correct anything so I went ahead and replaced all 3 ignition coils. This also has not solved anything. I can't see an O2 sensor causing all this and while I didn't get a code for it this seams to me the next thing to replace is the MAF. Ideas?
Thread Starter
Newbie
Joined: Jul 2010
Posts: 5
Likes: 0
From: Virginia
1997 E420, 1990 560 SEL, 1998 CLK 320
Unfortunatly I don't have live capabilities on my scanner, I am looking at finding a new scanner preferable one that links to a laptop.
I have not thought of fuel presure issues, is there a test I can do for that?
The wires to the coils are original.
Thanks for your time guys.
I have not thought of fuel presure issues, is there a test I can do for that?
The wires to the coils are original.
Thanks for your time guys.
