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Discussion Starter · #1 ·
Hi everyone,
I have a 2008 Mazda 3i w/2.0l. I been trying to find answers to what could be causing my mazda to have a check engine light and following with the code P2187. Here's what I think could be causing it:
One day, I went to go pump gas before heading out for a road trip and I accidentally overfilled the tank. (MY FIRST TIME DOING THAT) I proceeded to drive on the highway thinking it would okay since I'll be burning down the gas. Then when I arrived back home the car was still good until a few days later. My first ever check engine light came on and I was worried so I brought it to Autozone and it came out to be code: P2187. They first recommended I clean the MAF sensor in which it could be dirty. I did that and also rebooted the car by unplugging negative. Check engine light went away and then came back on again in a few hours. Now I am really concern. I see there's been more gas consumption, rough idle, and misfires between 2nd & 3rd gear. That's about it. Could it be purge valve solenoid? PCV?

Demon Spawn
758 Posts
does the car run/idle bad? here are potential causes of the code (if it is all you have it is a very unspecific code, if you have others post them so we can further assist this is a very generic code that isn't much help) it is a generic car running lean code (more air than their should be in the air fuel mix) start by checking to make sure all hoses are connected and connected tight air intake and all vacuum hoses once you have done this check to be sure there are no hose leaks, you can use soapy water in a spray bottle and spray it on the hoses with the car running, one section of hose at a time and see if you see any leaks (the soap will noticeably bubble a lot at a vacuum leak) or you can use flammable carburetor cleaner same way just listen for the engine to rev, if the engine revs when you spray part of a hose it has a vacuum leak and this hose must be changed, check the gas cap is tight and the rubber seal is nice and soft and has no rips or pieces missing or giant cracks (gas caps are cheap so replace this as a safe measure to be sure it isn't the cause) if the car idles bad it could be a big vacuum leak like a leaking gasket or a hose loose or off. a bad mass air flow sensor (the sensor near the air filter box) can cause this code and bad idle/loss of gas mileage and power or hard or no start, but will usually throw a code specific to the sensor on modern cars like the mazda 3, as the computer knows enough to diagnose this part. it could also be bad o2 sensors but again very unlikely as the 3 is smart enough to diagnose these parts and throw an 02 sensor specific code many times. could also be a fuel issue like a failing pump (usually these just wont work though, electric fuel pumps usually either work or don't) clogged fuel line or fuel rail, fouled injectors egr system issues but fuel system issues and egr clogging usually render the car almost un-drivable if not un-drivable.

If you do not have the skills or time to diagnose this you could be throwing money away on parts that don't fix it, it maybe worth your time and money and the hassle to take it to a shop if a new gas cap and checking the hoses for leaks don't solve it, as these generic codes can be hard to diagnose because its either something minor but the car knows there is an issue and cannot determine where or any bad parts or it is something major but has not set other codes yet (you can usually tell by how well it idles and drives) every time you relace something clear the codes either with a code reader or by disconnecting both battery terminals and letting it sit disconnected for a few minutes then reconnecting, this clears the code then drive for a day or 2 and if it doesn't come back or comes back with new ones it either didn't fix the issue or it found what the issue could be.

List of most potential causes
•Faulty O2 sensor (front)
•Faulty gas cap seal
•Leaky or loose oil filler cap
•Air leaking into the intake manifold downstream from the Mass Airflow sensor due to the manifold itself, vacuum hoses off or cracked, leak MAP sensor, Leak at turbo bypass or it's stuck open, power brake booster hose, or a leak in the EVAP system hoses.
•Faulty MAP sensor
•EVAP canister purge valve
•Fuel injector leak
•Fuel pressure regulator faulty
•Leaks in the exhaust system
•Faulty variable camshaft timing
•Faulty ECM (engine management computer)
•Faulty O2 preheater (front)
•Clogged fuel filter
•Fuel pump wearing out and producing low pressure.
•Faulty mass air flow sensor
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