Hi Scotty, 

Thanks for what you are doing. First-time driver and I learned a lot from you.

I bought a 2008 Hyundai Santa Fe with a 2.7L V6 engine about 10 000 miles ago, my first car. Now it has 169 000 miles. About 8 000 miles ago, 2-3 weeks after I changed the oil and did fuel injector cleaning, the Check Engine light turned on with P2187 and P2189 codes (System too lean ai Idle Bank 1 and Bank 2). I checked the gas tank cap (which was ok visually) and erased the code. The same code came back after two or three months of driving. After consulting with a local mechanic I erased the code again (thinking it's because of the bad quality gasoline).

After couple of weeks the check engine light came back again and turned off itself. I was driving on a highway on cruise control at 80 mph. While going up a small hill, the car got heated, the check engine light came on and I felt a strong gasoline smell. I stoped and let the car cool down. The check light went off itself and the car was driving fine.

I changed the engine oil and transmission fluid after 5000 miles (I didn't feel the gear change was smooth at the low gears) and drove for a month or two. The same codes came back. I ignored the light, but the car started hesitating, and I noticed the car was revving up and down slightly at the traffic light. I cleaned the MAF sensor and throttle body with an appropriate cleaner. The idling restored and the car hesitated less. But the same code came back after a couple of weeks. I drove for a while with the light on.

I tried to erase the code but it came back the same day. The car started hesitating again, no power, poor idleing, the rpm fluctuated at the traffic light to the point that the car started shaking and I had to turn off the engine and start again (the rpm at start (idle) was about 500). Sometimes the engine just died before I turned it off. The car started to get heated (I have to mention that I left the car idling several times for 15-20 min at the parking lot with no AC on before that). I checked the oil level and noticed the engine started to burn oil. I couldn't find any leaks (visually) and I just topped the oil little bit. Also I smelled the gasoline.  

Today, I changed the spark plugs, pcv valve, replaced the intack manifold gasket, the gasket between the intack manifold and throttle body and cleaned up throttle body and MAF sensor again. The air filter is clean. I checked the purge solenid valve by blowing in it (I didn't have vacuum pump) and it felt ok (it didn't pass any air). The car started to drive much better, no hesitation, no shaking. But the light came back right away. I haven't checked the code yet. But I am sure it is the same code. 

So what should I do?

Should I replace the purge solenoid valve? -> the car didn't start right away couple of times right after I refueled the car.

Or replace the throttle body -> I noticed that the valve inside the throttle body is inclined a little bit and there is a space for air to pass. I checked that when the battery was disconnected and I thought that when the car is on, the computer would adjust it. I also noticed some black spots between the throttle body and intack manifold. Does it mean the throttle body went bad.

Or replace the MAF sensor?

Or O2 sensor?

Or replace the fuel pump? I was traveling between cities and drove on a highway with low fuel level for a long time before I reached the gas station. Autozone doesn't sell fuel pump filter, because it comes with the fuel pump itself and I can not afford it. Could it be that fuel pump went bad and how can I test it?

Or replace the head gasket? I noticed some black spots from head gasket. But it is not leaking, not big and looks old to me. I was stupid and drove at very high speed, almost at max speed on a highway for extended time when I first bought the car, I was testing the car's limits. But it was about 9000 miles ago and there was no problems after that, no other codes other than mentioned above. Also I left the car several times idling with AC on for extended time in Arizona for some reasons. Could it be I damaged the engine? 

I can not ignore the code because I have to pass emission test.

I can not erase the code because it comes back almost right away.

I can not financially afford playing around with parts or go to a good mechanic.

Thanks for your help, your knowledge and advise.

Best regards and Happy Holidays

Aibek Mursalimov