[brodi3]

2000 E320 (W210). Got new battery Tuedsay pm as reported on another thread. Drove home perfectly. Wed morning drove a few blocks to friend's house, car ran awfully! Wouldn't rev, limped along, tried pumping accelerator, brief moments of full power, PIA, nothing I did would make it run correctly. Coming home tried very light touch on accelerator and got home fine, shifting correctly, working well as a grandpa's car. It starts perfectly, idles fine. Seems like fuel problem (too rich) to me, not battery. Visiting indie next Tues for analysis, code reads and I hope fix, but in meantime will have to drive wife's Honda Jazz (sigh!). Any thoughts?

 

[mrboca]

Sounds like adaptation issue. After the battery is disconnected, the ECU loses its adaptation data, and after the new battery is installed, it checks the systems one by one, and starts adaptation of running parameters based on the information from various sensors. The way you describe, points to a MAF sensor issue or pedal / throttle sensors / actuators.

Did they just change the battery, or did they check anything under the hood ?

 

[brodi3]

Only changed battery, nothing checked under hood and as I mentioned above, ran perfectly on way home (probably less than 2k, 1mile). When I described symptoms to indie he speculated that might be MAF issue. Won't know until he has a look next Tues. First thing is he will read codes which should give good idea. Started vehicle in last few minutes; problem stil there but I thought I could detect faint engine throb as if slight(?) misfire or similar.

 

[brodi3]

FIXED.
Had indie change MAF sensor (Bosch - OEM) as he felt the symptoms indicated bad MAF - bad MAF doesn't show as error code. MAF was the problem. Difference was amazing! Power and throttle response on drive home was a revelation. Indie commented that the MAF had probably been dying for some time with consequent slow loss of power, throttle response, increase in fuel consumption, all of which I had noticed. I have reset the odometer and will check fuel consumption in a few weeks - hoping for a difference.
I discussed

cleaning MAF ​

with indie but he said cleaning can give mixed results - might work for a while, probably won't so I spent the $ on new one.

 

[mrboca]

Glad it worked out for you. MAF sensor cleaning actually works, but to what extent for the hot film sensors like the one you got replaced, I do not know, as I have not had a MAF sensor issue. I cleaned MAF sensors for the Japanese cars I have, and it is really effective in restoring power and smoothing idle.

I would also replace the air filter, and give a good cleaning to the filter housing.