LilMsPris

I need help, I have a 2017 Malibu LT, NO check engine light is on but having problems with car hesitating when taking off from a stop. I have cleaned throttle body, new MAS, air filter changed, complete oil change, new spark plugs, Auto Zone had suggested a treatment I believe it was a fuel treatment can't remember for sure but poured it in gas tank, it was by Lucas that I do remember. I do live in the desert and I know heat can affect engine performance we have been in triple digits but it didn't do this last summer, I have had my Malibu 2 years and it has almost 68,000 miles on it. Car has not showed any signs of overheating, if I don't drive during the day but do when the sun goes down it seems to drive fine. Any suggestions? I'm worried my car doing this is going to mess something up and not having much luck finding anything online. I'm on a very tight budget and having to do a lot of the work myself so any help is much appreciated.

oilcanhenry

You need to have someone run some OBD II CODES on your Malibu. Stock plugs will go 100K or more. Did you ,mean MAF, not MAS, although it is likely the same. Lots of code won't send off your dash light.

LilMsPris

There are no codes. I went ahead today and put in a new O2 sensor. It's still doing it just not as bad. MAS was for mass air flow sensor.

oilcanhenry

It may be an air leak is my guess. Is there anywhere you can plug in a vacuum gauge?

LilMsPris

I don't even have a vacuum gauge

mountainmanjoe

can you read live data? What are the fuel trims?

Sounds a lot like sagging fuel pressure

LilMsPris

I have no idea ,how can I find that out?

oilcanhenry

As MMJ said, you can use an OBD II code reader to check your fuel trims. You may have a bad fuel pressure regulator or a fuel pump going bad. You can rent a fuel pressure gauge. It must be between
55 to 62 PSI with 60 PSI as Ideal.

oilcanhenry

They are cheap to purchase, but it's not easy to hook one up on a non-carbuerated system, i.e. a fuel-injected system. They can give you readings that can come in very handy, but F-I systems don't often come with the port outlet to hook them up to as you would have with a carb. There are adaptors that work on some F-I vehicles, but not all.