We own a 1995 E320 it has over 200,000 miles and ran like a champ. Recently it began running very rough at idle and giving off gas odor in the cab and outside of the car. The check engine light is on and I pulled the codes and got 4, 7, 10, and 26. Please help as to what I should do and where I should start.

Thank you

First check would be codes in the HFM module b/c you have an Ign code.............Pin #8

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A Dalton

How would I check that because I used the led light to get those codes

You build this simple tool.

E320 16 PIN DTC Charts inc. pin 8, pin 14

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A Dalton

At pin 8 I got code 22

Ok
Here are the 3 coils codes.
You have a code for coil 1 ..

21 Ignition output 3 or ignition coil for cylinder 1 and 6
22 Ignition output 1 or ignition coil for cylinder 2 and 5
23 Ignition output 2 or ignition coil for cylinder 3 and 4

Pull the cover to the coils and swap that coil with another..

Read this twice:

DO NOT swap anything else..take the connector under the coil OFF the offending coil when you do the swap b/c if you don't ,we will not know if the swap is the coil or plug connector.
Then run it and see if the code followed the coil...

If it does , [ 21 or 23] you have a bad coil ..if it stays code 22, you have a bad connector.

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A Dalton