2008 128i newly bought already getting p0174 and p0442 codes

[Crocacolaa]

2008 128i with P0174, P0442 codes

Car just hit 103k miles I bought the car at about 99k

This has been going on for months now, when I start the car it misfires and catches itself and starts to idle smoothly after 10 seconds. This happened the other day and sent the car into limp mode for 10-15 mins of driving then completely went away.

I just replaced the gas cap today still getting the P0442 code. The previous owner bought a new MAF sensor before he sold it to me, but I still went and bought a new one today and it’s literally changed nothing so I returned it.

I had a mechanic tell me it’s Plugs and coils and MAF sensor. But why would plug and coils cause these codes? I got lucky being able to return the MAF sensor I bought today but I don’t wanna buy new plugs and coils and it not remotely be a fix to this issue.

Any help would be appreciated

***UPDATE ON POST #8 GOOD NEWS***

[NorthernDancer]

The mechanic told you .................do you/we know more than him?
Do you know when the plugs & coils were last changed?
Most of us would automatically change coils & plugs if we bought a car with that many miles and we didn't get maintenance records. Pulling off the engine cover will give you the chance to see if there is a leaking VCG.
You have to pay to play; if you don't want to, buy a Toyota.

[fotontom]

Originally Posted by NorthernDancer

The mechanic told you .................do you/we know more than him?
Do you know when the plugs & coils were last changed?
Most of us would automatically change coils & plugs if we bought a car with that many miles and we didn't get maintenance records. Pulling off the engine cover will give you the chance to see if there is a leaking VCG.
You have to pay to play; if you don't want to, buy a Toyota.

Agree completely with Northern Dancer's comments. When I got my '12 with approximately the same mileage, I went right for the plugs. I do have a SULEV car, so I'll wait for 150K until I replace the coils. They will go, maybe one at a time, and it is not worth the effort of pulling the cover off the engine multiple times.

[DönerPorsche]

P0174 could also be caused by a vacuum leak, with limited information on the car I would start there.

[Crocacolaa]

Originally Posted by DönerPorsche

P0174 could also be caused by a vacuum leak, with limited information on the car I would start there.

I agree

I’m going to pay a shop to do a smoke test before I go out buying parts

Will clean the MAF sensor tonight with the CRC spray I just picked up but I docile that will fix it as I put in a new MAF today and it did nothing

[Gangplank]

At that mileage you are due for plugs. I'd start with spark plugs and smoke test. Clean the MAF, new air filter. See if that fixes the code

Are you using a good Indy shop or dealer?

Also at that mileage unless you have records change power steering fluid, brake fluid, and coolant. At a minimum.

[Thunderguts]

The 128i really doesn't live up to the German maintenance nightmare legend. It has a few problem areas and one in particular is difficult to address (oil pan gasket), but otherwise they aren't THAT bad. You don't need to be rich to maintain one properly, but you do need to set aside a little repair money.

A complete set of coils and plugs will cost you around $230.
A water pump, thermostat, and coolant are $370.
An ESS and valve cover gasket kit is $300
A power steering reservoir kit is $40

Change all of those things and you'll take care of most of the problem areas of a higher mileage car. All of these can be changed in a garage without much effort. The oil pan gasket is the outlier. That one is a pain. The gasket is cheap, but you'll still likely need a lot of specialty tools.

[Crocacolaa]

***UPDATE***

Wow 🤩

I cleaned the MAF sensor and let it sit disconnected overnight to ensure it dries properly and I’ve been driving my car ALL day and ZERO idling issues

I’m in shock, I was about to drop $1500 on so many parts. Now, this is the thing. I still have the CEL lights but shouldn’t that clear itself after a few cycles?

Car is running great zero rough idle when I start the car cold there’s zero shaking anymore

[Afam28]

I would still follow the advice mentioned above...
Start your own maintenance records and build from there...

[Crocacolaa]

Originally Posted by Afam28

I would still follow the advice mentioned above...
Start your own maintenance records and build from there...

I will thank you

And it just came back again :/

[Crocacolaa]

Bump

[Gangplank]

Originally Posted by Crocacolaa

Bump

Bump. See my advice above.