Have read a number of threads, usually with suggestions but not any posted results.

1999 S420 147k (yes I drive it, ALOT) usually average 3000-4000 per month.

On Monday I was headed to airport. Very happy as I just had upper and lower ball joints done, got rid of the horrible second set of Lemfoerder coil springs and a spiffy new set of 255/45 18 Michelin Pilot Sports installed. Was enjoying the smooth responsive 1 hour trek to airport.

When I arrived at airport, got myself into garage and was headed up to the upper levels to park for the couple days I was to be away. Upon entering the first incline the car stalled while driving. Couldn't get it started. So of course a dozen culprits flash through my mind. Would turn over, but a second or two it would die again.

I went looking for the parking office to garner some assistance. Found no one.

Returned ten minutes later, tried again and no start. Same deal.

Sitting there contemplating the business trip to Dallas, I tried again and by manipulating the pedal I could get it to start and run but if I let off it would die. At this point, I had no check engine light come up but the whole dash lit up when it stalled.

I was able to 'power brake' it into a nearby parking spot, and I decided to get in my flight and deal with it when I got back.

Last night, I decided I had to at least get it out of the airport garage because no tow truck could load within the garage. Once I got going, I kept going knowing my route had good phone service if I needed to call AAA.

Keeping the RPMs up, I made it home. It died in driveway. Did notice that the MPG gauge needle was swaying back and forth between 15 and 35 the whole way home, but otherwise no issues with power once accelerating.

This morning, I set out to do a precursory inspection of the items I felt could cause this. First checked the basics - K&N filters clean (recharged a month ago), no obvious vacuum leaks, fuel pump humming away with key on and still no check engine light. Ok, I thought, now to get into it.

I removed MAF and gave that a cleaning. It looked clean, but I did it anyway. Looked at throttle body and it too was clean. Looked inside plenum and it looked good. MAF gasket was whole and showed no cracks. Couple new clamps and I reassembled. Checking torx bolts on throttle body for proper seating and tried to start. Same issue.

Thinking there MUST be a massive vacuum leak, I rechecked all the lines. Broke the plastic of the front most line and replaced it. Then thinking that maybe I had a brake booster failing, I disconnected it, plugged holes and tried starting. No difference.

At this point I got a check engine light.

Now I am awaiting a friend of my mechanic to stop in tomorrow night to read code (mechanic just had stints put in and is out of commission for a bit) but I am wondering if there is something else for me to check?

Plugs have 10k and two I pulled looked good. Suppose I could pull all of them and make sure. I religiously use Techron every 5k. Fuel tank over half full.

As of a few moments ago when I needed to move the car to get my Zetec powered Vanagon out of driveway to use tomorrow the MPG needle is pegged all way to left.

When I get car going, and manipulate the pedal, I notice no skipping or misfires, but I could be wrong (frequently am according to wife)

What am I missing here?

Pre owned CLS550 at dealership this morning is looking better every moment.

 

the only reason i kno of for an automatic car to stall on u is because of a bad battery. then again theres also something called a limp mode. when one of my coil packs went bad, which is my cars answer to a bad idle, my car wouldnt go above a certain rpm and it was literally limping along. its a feature that u have when ur car needs a part thats dire to the cars health it will limp along so u dont damage anything further.

 

Not in limp mode. Had that once in my E420.

Did not think of battery as I cranked it over multiple times without a hiccup.

 

yea it will crank but unless ur on the throttle it will cut off. it could be a poor battery. not a useless battery but close to it. id check it. i was in this guys bmw before and i start it up i go to put it to drive and i realized it cut off on me like i stalled. he said he needs a new battery. before that i never knew it was possible to stall an automatic car.

 

id check it u seamed to check everything else right.

 

pull all plugs to check if bad coil,the bad plugs will be wet.
I hope it is a simple fix,as S Class cars usssally don't have problems

 

A fuel injected car will not respond to throttle movement..

 

hey contradicting **** caressing eddie. you know nothing about cars. stick to the things u know like **** and *****.

 

castilleja96 did u figure out whats wrong with you car?

 

I know a hundred times more than you do Dick

 

Its not even castilleja96 car that needs help.. Your on your game cocka doo

 

chojinchef happens to be a great customer of mine and Im not sure if he got his car straightened out... Must be the coil packs..lol

 

yea what does he do call u up for a blow job. im talking about keeping the rpms up ya dumb ****. like i said stick to give out blow jobs

 

How imature are you? I would think the moderator would ban you from this forum..you dont have much information to add...

 

Rough running when hot or stumbling or dying only when hot is caused by the purge valve. Pinch the hose and if the car runs better that's your answer. It creates a vacuum in the gas tank so great that the fuel pump can't siphon fuel also it makes the engine run so rich that it will have bad acceleration
Misfire at idle. Run worse when ac is on. Hope this helps to all those that don't have a answer and all those tired of reading forums that no one ever posts the fixes too.