Menace65

Please Help, My E420 has 191k Miles on it. I live in a warm climate, when the outside temp is below 75f and the car has been sitting over night when I start it up it bucks and backfires for about 2 minutes, then it will idle high around 1500rpm and run rough. At the same time the codes and errors are showing up on the dash. Once the engine temp reaches about 90c I turn it off and restart and then it will idle back down to a normal 500-700 rpm and run great until the next morning. The only other thing I have a problem with is sometimes when at a drive thru or long light it will idle a bit rough but has never stalled. Over the warm summer months had no trouble at all. Currently I am in Michigan so it takes a lot longer to get to 90c. Any help would be great.

I Have replaced a bad rubber hose that goes between the valve cover and intake manifold and also the rubber boot between the MAF and Throttle Body

Idarknight

I have a 2000 E430 Sport with 159k mi on it... A dream!! But I am having some of the same problems. I can start it up for the first time in the morning and it will start fine. Any other time after that it will turn over for a long time but not catch. If it fails to start I'll have to lightly put my foot on the accelerator to help it start. Then while it is idling, it lopes like it's out of time or there is a bad plug and wire. I recently had the plugs changed but the prob still exists. Now the"Check Engine" light is illuminated. While sitting at a light with my foot on the brake, the engine lopes really bad and the car bucks. While accelerating and driving at normal speeds, the car does fine. Please, what is going on???

erikfrancin

my car was hesitant to start a while ago and it turned out to be the fuel filter. might want to consider that BUT i never had any issues with the idle...

Idarknight

How much did the fuel filter run you? And was it a chore to change? For the 1st year of owning my e430 sport, I figured I'd let Benz techs at a local Benz service center.... not the dealer though, perform the work on it and then I'll start doing it myself after that.

erikfrancin

if my car wasn't so low, it would have been a 15 minute job...

it was truly one of the easiet repairs / maintenance tasks i've ever untaken myself.

i used an oem filter from the dealership as was recommended on this forum (the filter has a check valve in it which is much more prone to fail prematurely on aftermarket filters from what i read) and i want to say it cost me approx $65 at the parts counter and the guy threw in new hose clamps at no charge....

Idarknight

Awesome!! Thanks!! I really appreciate your help. I'm going to check this out this week and see how lucky I can get.... LOL...

Thanks again!

erikfrancin

Definitely worth a shot! Worst case, you can justify it as preventative maintenance right? Hehe. Merry Christmas!

Idarknight

Hey erikfancin!!! Happy New Year to you and yours! Just wanted to give you a quick update on what has transpired with my E430 Sport. I did as you suggested, change the fuel filter. This was a much needed replacement but still didn't resolve my problem. So I had the wires changed out... Still no progress. After about a month of trial and error from my indy tech shop, it turned out to be the K40 module. This was the culprit that seemed to be throwing out the wrong amperage to the car and kept it from idling and starting. It's not at 100% just now because I still have to replace, both, the right and left catalysts but the car runs like a dream even with bad catalysts.

Know of anything I can do to get my cigarette lighter back working besides checking the fuses in all 3 locations? It's kind of annoying not having it for my radar detector and GPS. But anything you can suggest will be greatly appreciated.

Thanks!