[Performance plus]

Hi new to the site and new to benz cars. Mine seems to be hesitating and falling on its face almost then sometimes it will accelerate normal after or kinda just continue lazily, i have cleaned mass air replaced fuel filter and it has 60 psi fuel pressure. i get no codes and have no pending codes. throttle trim seems to follow gas pedal while driving with scantool mass air does increase air flow readings as well. (not sure it of what it should be reading) it does have 170,000 miles on it now, but has been dealer maintained. I am second owner.when purchased the car it neededa crank sensor and i did replace that and car was awsome for few months then this started, Id prefer not to just throw parts at it but im at wits end

 

[insame1]

First I have to ask if the exclamation point lights up on the dash when it is choking? If not I would test the cats.

 

[Performance plus]

no its not the traction control kickin in,and highly doubt its converters seeing it did it suddenly and i know what plugged cats feel like. i thought it was i got bad fuel cuz it was that sudden.

 

[Check Codes]

If there are truly no codes (do you have a code reader or just the scantool?), then I'd be inclined to pay for some live-data diagnostics. That's cheaper than throwing parts at it and more likely to find a solution.

However, I would first suggest that you do the adaptive-shift reset, it's possible that went wonky for some reason. The procedure is detailed in the W210 forum help/diy stickies.

And of course check the operation of the W/S switch to be sure it's functioning and not stuck in "W."

Good luck.

 

[Performance plus]

I have two scan tools can do live data graphing etc. even looked for pending codes of course, the transmission shifts same as it always did since i got it, drove it in live data mode already. wanted to get it figured out b4 i put it away for the winter,but not looking good. loved the car till now lol

 

[scottys209]

Oh, the possibilities... Vacuum leak, clogged injectors, faulty wires, coil packs failing, MAF failing, intake manifold gaskets, spark plugs. Check for vacuum leaks / air leaks around the MAF/Throttle body with carb cleaner, pull some plugs and see what they look like, who knows man, may be original. Sea Foam it. Then go from there... Dealer Maintained doesn't necessarily mean the first owner did all the recommended services, it just means he did some services, but did them at the dealer.

 

[Performance plus]

I did check for vacumn leaks.I also have stack of repair records like a book guy was anal with this car, but havent gone thru them yet looks like i will be tho, I notice sometimes if i push the pedal slow it seems better . it feels like it lacks a 100 hp tho right now, as far as plugs etc wouldnt it throw a misfire code? Most on here seem to have this problem say maf, i did clean it and its same. Next i guess maybe check fuel pressure while driving down road if can locate gauge with long enuff hose.

 

[scottys209]

It wouldn't necessarily throw a misfire code... Cleaning a MAF works probably 30% of the time, 70% of the time it needs to be replaced.

I did check for vacumn leaks.I also have stack of repair records like a book guy was anal with this car, but havent gone thru them yet looks like i will be tho, I notice sometimes if i push the pedal slow it seems better . it feels like it lacks a 100 hp tho right now, as far as plugs etc wouldnt it throw a misfire code? Most on here seem to have this problem say maf, i did clean it and its same. Next i guess maybe check fuel pressure while driving down road if can locate gauge with long enuff hose.

 

[A1EK]

I would say personaly its likely to be your MAF. I know you've said you've cleaned it, however this does not always eleviate the problem and does not always show up as a fault in the codes even if they are going bad.

Have you tried disconnecting the MAF and if you find your car runs better then it would suggest the fault is here.

 

[scottys209]

+1 30/70% cleaning works vs replacing it. Maybe even lower.

I would say personaly its likely to be your MAF. I know you've said you've cleaned it, however this does not always eleviate the problem and does not always show up as a fault in the codes even if they are going bad.

Have you tried disconnecting the MAF and if you find your car runs better then it would suggest the fault is here.

 

[achoren]

+1 on the MAF. If replacement wasn't done in the recent service records, I'd forgo cleaning and buy a new one. A simple DIY and will likely need to be done anyways sooner than later.

 

[Performance plus]

Yea my plan was to just replace it at this point . oddly its been back to normal it seems for two tanks of gas. I did take it out and pound it badly and did a few high speed highway runs to try and make code show up.

 

[A1EK]

Yea my plan was to just replace it at this point . oddly its been back to normal it seems for two tanks of gas. I did take it out and pound it badly and did a few high speed highway runs to try and make code show up.

Have you not unplugged it and tried yet?

 

[Performance plus]

Havnet had chance to do anything including unplug the maf,weather sucks here and shophas been crazy. Hoping soon tho

 

[bobbyjo9]

If the MAF doesn't work for you, I'd be looking at the TPS. It will tend to act normal under normal driving. Floor it and you'll have stumbles and pops followed by a very lazy shifting trans till you cycle the key. Then all will appear normal till you floor it again. They are about $125 online and all of 5 minutes to replace.

 

[Performance plus]

Funny that you mention tps because i have noticed when i do drive it even tho the live data says its following my pedal input it seems to pull reall hard if ya keep it no more than 1/4 to half throttle if you go beyond that it lacks and power falls off. im trying to get a fuel pressure reading under full load to eliminate pump pressure also. Just not enuff hours in the day.