Service Engine Soom came on the day after I had my air filter changed. Do you think it wasnt installed properly?

It's possible, but not necessarily the case. While a poorly installed air filter *could* trigger a Service Engine Soon light (SES), it's not the most common cause. The SES light is a general indicator of a problem detected by the car's computer. The air filter's impact on the engine is indirect. A severely restricted air filter might cause a lean condition (too much air), which the computer could detect. However, it's more likely that the light was triggered by an unrelated issue that just happened to coincide with the filter change.

Here's why it might be unrelated:

* Coincidence: The problem existed before the filter change and just happened to manifest the next day.

* Other issues: Many things can trigger the SES light, including problems with the oxygen sensor, mass airflow sensor, catalytic converter, ignition system, and more.

What you should do:

1. Get the code read: Take your car to an auto parts store (like AutoZone or O'Reilly's); most offer free diagnostic code reading. This will give you the specific trouble code, which will point to the problem.

2. Don't assume it's the air filter: Even if the code *seems* related to air intake, don't automatically blame the filter installation. Have a mechanic diagnose the issue properly.

3. If you're concerned about the filter installation: If the code reading is inconclusive or points to something related to air intake, you *can* ask the mechanic or the place that changed your filter to double-check their work. However, it's more efficient to address the actual problem indicated by the trouble code.

In short, while a faulty air filter installation is *possible*, it's not the most likely scenario. Get the diagnostic code read to pinpoint the actual cause.