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Ron, ASE Certified Technician
Category: Ford
Satisfied Customers: 23821
Experience:  23 years with Ford specializing in drivability and electrical and AC. Ford certs and ASE Certs
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The engine light comes on in my 2013 ford focus ecoboost and

Customer Question

the engine light comes on in my 2013 ford focus ecoboost and sometimes it says that their was a failure during start up. And when you drive it there is a lot of hesitation and doesn't want to accelerate. But then when you turn the car off and back on sometimes it goes away and its normal. taken it into a mechanic and he doesn't know whats up.
Submitted: 2 years ago via
Category: Ford
Expert:  Jan Andersson replied 2 years ago.
Hi, The first thing that comes to mind is a misfire. The symptoms fit the bill. BUT, I don't want to just guess and jump to conclusions. I'd need to know the engine trouble code(s). Any time the check engine light comes on, a trouble code is stored. it will give valuable info on what was going wrong, at least point in the right direction. Modern engines have way too many electronic sensors and circuits controlling the engine, to diagnose each one individually without a scanner tool. Reading the code is your first step. Your mechanic probably did that, but we need to know the codes. You can take the car to any auto parts store, and they will likely read the codes for free. tell them not to erase them, just read. Some are hesitant to erase them due to liability concerns. One code for misfire is something like "misfire detected in the first 1000 rpms", meaning at startup. Maybe thats what he was talking about. Turbo engines have higher cylinder pressures under boost (acceleration), making misfires happen more easily when the ignition system is not 100%. Let me know if you have the codes or if you can get them. In the meantime, do not accelerate hard or drive on the highway, or further damage may occur. Limit your driving to a minimum. If the check engine light is blinking while driving, it usually means a misfire is happening right then, and you should let off the throttle and take it easy. If this happens frequently, I would not drive at all, period. It causes unburnt fuel to pass through into the exhaust and catalytic converters, and it could damage them.
Customer: replied 2 years ago.
The mechanic read the codes and said it was the map sensor located in the air intake manifold. So he replaced that but it didn't fix the problem and now he is out of ideas so now were back to square one. So if I get the codes from him what should I do with them?
Expert:  Jan Andersson replied 2 years ago.
Just copy them here and we'll see. All I need is the alphanumeric code, like P0301 for example. If you are still working with him, I would suggets he runs the engine and monitors sensor data with a scanner tool that can show live data, maybe he can spot something that's out of range or doesn't make sense. O2 sensor data, fuel trim values, for example. Would like to see if it's running rich or lean, if its' trying to add or reduce amount of fuel being injected.... stuff like that. Check temperature sensor data, Intake air and coolant temperatures come to mind. If a sensor is bad it could tell the computer it's -40F and the computer injects too much fuel.
Customer: replied 2 years ago.
so will I be able to talk to you tomorrow if I just leave this page up? or will I have to pay again and try and find you?
Expert:  Jan Andersson replied 2 years ago.
You should be able to come back to this discussion and we can continue tomorrow. No need to pay twice. We don't get paid at all until you indicate that you have received a satisfactory answer to your question. You have credit in the system now and it won't be used without your approval. Payment is not triggered until you rate an answer with a positive rating or "accept" it, whichever function is offered on your screen. On my screen there is a check box "I am ready to be rated", until I check it, you should not be presented with these choices. We are just getting started, it will take some back and forth communication. I am blind, and I need your input to know whats going on with the car.
Customer: replied 2 years ago.
we went to the mechanic and the only code that came up when they plugged the car in was P0106 which is the map sensor which we already replaced and it didn't fix the problem.
Expert:  Jan Andersson replied 2 years ago.
monitor map pressure reading on a scanner while blipping the throttle and letting rpms climb, then quickly taking foot off throttle. Check BARO pressure reading too. At idle the two should be close. One is intake manifold pressure, other is athmospheric pressure. Look for vacuum hose leaks or intake leaks between MAF sensor and throttle body. Check and tighten all boost hose/pipe fittings on the intake side as needed. They may only leak under boost. You didn't say anything about live data monitoring, if your mechanic can only read the codes, maybe you should find a better mechanic who can do diagnostic work. No offense, there are just many levels of "mechanics" out there. Ask for a Master Tech, they at least used to have enough theoretical knowledge to pass diagnostic certification tests..... You could call a dealership and see if they would agree that this is an emissions component failure (It does have direct impact on emissions), those have federally mandated longer warranty periods, 8 years/80.000 miles if I am not mistaken. You might be able to get it fixed for free.