A happy new year to everyone!
Yesterday, wife's ML 430 (MY 2000, 98k miles) hesitated to accelerate on pressing the gas pedal, eventually CEL turned on and my iCarsoft i980 reader pulled the codes P0170 and P0173. A quick search on this forum suggests that this could be because of a bad MAF or the fuel pump or some leak in the air intake, or the cats, or ...
Today I cleaned the MAF, cleared codes, then took the car our for a ride and, yes, when pressing hard on the gas, the engine doesn't fully rev up. After about 15 minutes it gets worse and the engine sputters and has a rough idle, but when being soft on the gas, it still drives its 30mph, CEL eventually on.
I am wondering if I should replace the MAF before I bring it in to my local indie shop? MAF has last been replaced on 05/14/10 at 62k miles. Air filter is new. Fuel filter has been upgraded and replaced on 09/23/09 at 58k miles.
I have only limited tools and mechanical abilities (I am able to replace the MAF on the ML 430, but, today, I failed to take out the MAF on my w209 for swapping it with the ML :-(). The i980 scanner has live-stream data that might be useful. The attached screenshots are after resetting the car (disconnecting the battery) and idling for a minute or two. I wonder if any of these values would point towards a particular component that should be checked? Before the reset during my clean-the-MAF-and-drive-test I found that intake manifold air pressure and measured airflow by the MAF were increasing/decreasing according to engine RPM (as I would have expected).
I can take more measurements of the streaming data if helpful. I don't have a pressure gauge for measuring fuel pressure, but if someone tells me what to get and how to measure then I am willing to get the equipment. However, if turns out to be the fuel pump (or the cats, or something beyond my abilities), then please don't be disappointed if I take it to the shop.
Yesterday, wife's ML 430 (MY 2000, 98k miles) hesitated to accelerate on pressing the gas pedal, eventually CEL turned on and my iCarsoft i980 reader pulled the codes P0170 and P0173. A quick search on this forum suggests that this could be because of a bad MAF or the fuel pump or some leak in the air intake, or the cats, or ...
Today I cleaned the MAF, cleared codes, then took the car our for a ride and, yes, when pressing hard on the gas, the engine doesn't fully rev up. After about 15 minutes it gets worse and the engine sputters and has a rough idle, but when being soft on the gas, it still drives its 30mph, CEL eventually on.
I am wondering if I should replace the MAF before I bring it in to my local indie shop? MAF has last been replaced on 05/14/10 at 62k miles. Air filter is new. Fuel filter has been upgraded and replaced on 09/23/09 at 58k miles.
I have only limited tools and mechanical abilities (I am able to replace the MAF on the ML 430, but, today, I failed to take out the MAF on my w209 for swapping it with the ML :-(). The i980 scanner has live-stream data that might be useful. The attached screenshots are after resetting the car (disconnecting the battery) and idling for a minute or two. I wonder if any of these values would point towards a particular component that should be checked? Before the reset during my clean-the-MAF-and-drive-test I found that intake manifold air pressure and measured airflow by the MAF were increasing/decreasing according to engine RPM (as I would have expected).
I can take more measurements of the streaming data if helpful. I don't have a pressure gauge for measuring fuel pressure, but if someone tells me what to get and how to measure then I am willing to get the equipment. However, if turns out to be the fuel pump (or the cats, or something beyond my abilities), then please don't be disappointed if I take it to the shop.