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Hi this is Mike. I was taking my car into a service center to check my car health call Bimmer rescue and gave me a report that pretty much said that the intake manifold needed to be replaced but I did it myself because I have a tight budget so the first time I didn’t properly torque down the bolts and lead to these codes. So I took it out again and sure enough the gaskets were scraped in some spots. I got new gasket's and o-rings for the injector put it all back. I didn’t get the same engine till yesterday in Newport at idle (twice the codes came up when it was about 585 or somewhere about idle) and today I was trying to pull out and it hesitated a huge amount till about a few seconds. I don’t know what happening, I’m thinking maybe vacuum leak, I’m looking for advice cause I think I’m gonna lost my mind a little with this lol.
edit: this is an 2011 Mercedes-Benz C300 and the work that been done with it below.
Last edited by MikesMB11300; Jun 1, 2025 at 06:18 AM.
Someone recently posted about getting codes for running too rich. Your issue could be similar. Something not installed back properly, air box seal, some type of leak allowing unmetered air in.
Someone recently posted about getting codes for running too rich. Your issue could be similar. Something not installed back properly, air box seal, some type of leak allowing unmetered air in.
Im not sure how detailed that scanner can pick up fault codes. Where there any other fault codes?
I probably done something incorrect and I wouldn’t be surprised because I’ve done small things before but this was my first time doing this extensively and it was just cheap code reader I could use.
Ok so update I was looking around in the engine to see if there was going about the June 1st to make sure I can make it down to the airport (family and I currently on vacation) and found that I forgot the hoes that connects between the MAF sensor and throttle body (I thinks it called the crankshaft?) and that help with it from dropping as much.(kind of forgot cause it been a few day) but I do have a few questions like I use cruse control a lot so when I turn it off like letting of the gas is it supposed to go down a little to like for example from 1900~ to 1780~ at like 60~ mph? It was like this when I bought the car and I thought it was normal but honestly after look more into the car I’m not sure. My second question is what is the fuel economy on this engine supposed to be? Online I’m being told 24-26 mpg another said 30.4, and based of buying this car was saying 17 city and 21 highway. I get it based of your driving but some days I’ll will get like 31 mpg and then other days 23-25(I do live in a the middle of nowhere with a bunch of old people around so idk I just would like an idea of what I should be getting) I’ll give more updates when I get back from vacation.
I never use cruise control so not sure. I dont even know how to use it.
I have the M272 with 160,000 miles and I drive normal, no speeding around or racing the engine. Around town the average MPG will be around 19-22. Cruising on the highway 25-28. Thats combined miles driven from start.
Yeah it’s a M272.
The cruise control isn’t too hard to understand, there’s a stock above the indicators and headlight, Mercedes has a video.
thank you though cause the day I did find that hoes that wasn’t put on. I did get about 28 mpg though it has only been one drive. I did check if there was any pending cods or something and came back with nothing. So I am more confident that I have fixed the issue. I do think there a small vacuum leak since when you let of the gas the rpm lower just a small bit so I’ll still check on that.
May be worth investing in a Mercedes specific scanner. I have a Foxwell that works great, got it mainly to read the transmission fluid temp for servicing it. Its not touch screen though, if I were to get another I would probably get a Launch.
Can search around for deals, Amazon or AliExpress. I've seen them under $100.
My gas mileage has been much higher than it was previously.
Since I had the car around 5yrs now I never saw it go past 25mpg. Around town id check and see it around 19mpg.
This past winter I did nothing to the car, didnt work on it or replace anything. Only thing I can think of is I did buy 2 big value size bottles of Techron. I used one bottle per the directions, 1oz/gallon. Then the 2nd bottle I would use 2oz when getting gas, wasnt a full tank since like to get gas before it hits 1/4.
I dont put many miles on the car so it took me awhile. Then I started seeing the gas mile go up and up. Went to the store earlier driving backroads and saw it at above 23mpg. I'll also say the car is running fantastic.
May be worth investing in a Mercedes specific scanner. I have a Foxwell that works great, got it mainly to read the transmission fluid temp for servicing it. Its not touch screen though, if I were to get another I would probably get a Launch.
Can search around for deals, Amazon or AliExpress. I've seen them under $100.
The 4 below I hear are all good.
Thank you very much🙏
if I had this to check the transmission, it probably wouldn’t had been so messy for lol
My gas mileage has been much higher than it was previously.
Since I had the car around 5yrs now I never saw it go past 25mpg. Around town id check and see it around 19mpg.
This past winter I did nothing to the car, didnt work on it or replace anything. Only thing I can think of is I did buy 2 big value size bottles of Techron. I used one bottle per the directions, 1oz/gallon. Then the 2nd bottle I would use 2oz when getting gas, wasnt a full tank since like to get gas before it hits 1/4.
I dont put many miles on the car so it took me awhile. Then I started seeing the gas mile go up and up. Went to the store earlier driving backroads and saw it at above 23mpg. I'll also say the car is running fantastic.
Ok I got ya, I’ll send pics of mine when I get back cause the only time I would get 23~ is when it’s raining or something. Any other time it about 27-29~ though I do remember one time I was heading home from a friends college and was getting like 31.4 but also and check engine like that bank 1 was rich. So idk what to really expect out of an V6 lol
I did get fuel cleaner and see if that was the case long ago but I should keep doing that since I’ll be getting close now to 100k. Do you recommend that?
I have been using Techron for over 20yrs in all my vehicles. I'll usually put a bottle in the gas tank once or twice a year. I've never used it to "fix" an issue, more like i'll be at stop lights and the engine doesnt seem to be running perfectly smooth, very slight vibration or rough idle. Add a bottle and then forget about it because it seems to be back to normal. Guess you can say its more preventative maintenance than curative, use it to clean things before it becomes an issue. I wouldnt go overboard with it which is why I only added a small amount with the 2nd bottle. I usually get gas at Gulf so im not worried about bad gas, just want that extra cleaning ability.
I'll get it at my local Napa Autoparts when its on sale. Right now its $12.99 for the 32oz bottle.
I've also used Seafoam though I get that mostly for my small engines. I think that stuff 100% works at keeping gas fresh in my containers. I have a small lawn and it only takes me 20 minutes to mow it so my 2 gallon gas container lasts me all year and i've never had any fuel related issues with my mower, weed eater or snow blower. I'll even leave gas in my pressure washer all year and that thing starts 1st pull every time.
Ok I got you. probably will try that out and I also had gotten that Launch diagnosis. i'll show you what I get when I check my car today.
also I drove the last few days and yesterday and got about 28-29 but later yesterday I got the same code again that it was too lean.
Last edited by MikesMB11300; Jun 13, 2025 at 02:49 PM.
Reason: Adding something
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