1999 Mercedes E430. Sometimes it will start,

Does it try to start, but not catch? That sounds like a fuel pump going bad if you press the gas pedal twice and it starts. You should not have to press the gas pedal in an e430 to get it to start up.

We have had check engine lights on all vehicles
for 35 years--so why the question?

Check for OBD Codes,look them up & diagnose them

try undoing eath again on battery leave for harf an hour then reconnect the earth lead and try again.

replace the dynamo solenoid

on the fuse door

check your gas cap it might not be venting the tank properly remove gas can and see if that helps

There should be a red lever under the steering wheel, VERY close to the firewall. Sometimes it is hard to see because they tend to put it up into the dash a little.

i have a 2000 clk320. it would not start sometimes, the engine would crank but it wont start. but after an hour or so it would start. sometime i'll get somewhere park, and come out an hour later and the engine would not start. if your having the same problem, take it to autoparts store ex: autozone or kragen. they could check your battery for free. and if its not the battery. than it could either be your fuel pump. or the crank position sensor. good luck. hopefully this help.

all you need to do is call 765-448-4582..give them the vin# and they will give it to u for free.. good luck and thanks for using fixya.com...keith..

sounds like spider injectors there like $450 alone mine did that last winter looking at easy 700 to fix