i have a misfire on cylinder six.

ANSWER : Without checking the ignition coils and spark plugs myself for proper spark output I would say the engine is misfiring and may be the coils and plugs. It is also common for the valve cover gasket to leak oil into the spark plug tubes shorting the coil and spark plug out so it cannot fire. The check engine light is flashing due to the misfire is active and additional catalyst damage can happen if you keep driving with the misfire and raw fuel dumping into the catalyst. I would recommend having a mobile mechanic like one from YourMechanic come and do a through diagnosis to see if the valve gasket is leaking into the spark plugs and caused damage to the coils and spark plugs. If it is leaking then the valve cover gasket should be replaced with the spark plugs and contaminated ignition coils replaced then computer codes an be cleared and the vehicle road tested for any other problems from driving the vehicle with the engine misfiring.

ANSWER : A misfire to cylinder 1 may be a fuel pressure regulator sensor problem but it is most likely due to a clogged injector on number one. You will need to scan and view data to see if fuel pressure sensor is needing replacement first. Then have the injectors cleansed to see if the codes go away.

I’d suggest you get this looked at by a qualified technician who can perform these checks to diagnose your Check Engine Light and make the appropriate repairs to your vehicle.

ANSWER : This may be a problem with the exhaust catalyst partly clogged causing excessive back pressure. There is a test where the O2 sensor is removed and the back pressure tester is put in the hole to see if the catalyst is clogged.

The computer should be scanned to see if you are running lean from bad O2 sensors or for some other reason. The coil may also be weak and not putting out enough spark energy. Have the system checked by a mechanic since this truck engine may have exhaust problems, engine carbon build up, cracked valve seats, O2 sensor problems, coil problems, camshaft and distributor cam gear worn problems. The list goes on and will require a qualified mechanic time to diagnose this complaint for you. If a shop or mechanic cannot figure it out then it may take a factory trained mechanic to be able to diagnose the problem down to one of the listed issues. The best thing to recommend is to replace all the tune up items first so these can be eliminated. This means coils, plugs, wires, fuel filter and air filter, and PCV valve.

ANSWER : Hello. It sounds like you may have the wrong parts installed on the car. Due to the fact that multiple people have worked on it you may have some parts that do not meet specifications. From what it sounds like to me though you either do not have an ECM in the vehicle with the correct programming or you have a connection issue. If all of the grounds are not clean and tight then that will cause this. if they are then the computer needs to be programmed to your vehicle at the dealer and that may take care of it.

ANSWER : Hello. From your description this can be caused by a few things. The oil smell tells me that your either have an external oil leak that is causing this or you may have a valve seal or piston ring problem that will require some serious engine work. I usually check the engine for any external leaks as oil getting on the ignition system components will cause it to misfire. If there are not any external issues then I do a compression test to see if the problem is internal. If you are planning on having this misfire and oil smell diagnosed, consider YourMechanic, as a certified mechanic can come to your home or office to take a look at it.

ANSWER : The variance in cylinder compression you are reporting exceeds that allowed in the Factory Service Manual. Put oil in the No. 2 cylinder to see if compression rises appreciably and you can then rule in or out leaks past the rings (the oil has the effect of sealing the rings). If compression is not higher with oil, the head gasket and/or valves are leaking and that may be a part cause of the misfiring. If those components are leaking, the engine will have to be repaired. There is always a possibility of an electrical fault in the injector circuit, so you can evaluate that and, as well, look at the secondary firing pattern in cylinder two which will provide clues as to what exactly is going on in that cylinder. If you desire a more conclusive diagnostic, please request a misfiring diagnostic and the responding certified mechanic will get this taken care of for you. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.

ANSWER : Hello! We will be happy to assist. You have definitely been on the right path to finding the root of the misfire. However there are a few things left that I recommend checking. I suggest to check the spark at the spark plugs at each cylinder. There may be an issue with the coil pack causing the misfire. Also check the PCV valve because that is a known cause of a misfires on your particular vehicle. I suspect that the PCV valve and hose may be leaking and causing the misfire.

You may have the engine model which has the PCV valve located above the transmission next to the exhaust header. This engine model’s PCV valve is routinely looked over because most are unaware that there are two PCV valve systems and the first one is easily visible from the top. I also recommend checking the resistance and voltages at the coil packs with a multimeter. I have a friend whom worked as a technician at a Ford dealership once tell me of a problem with your generation of Focus in which the wiring to the coil packs were made too tight and the tension broke the wires overtime.

I would always recommend having a qualified mechanic, such as one from YourMechanic, assist you in diagnosing your engine misfire and assisting you in repairs.

ANSWER : Driving for an extended period with a misfiring cylinder can certainly do damage. That cylinder will run hotter because of the misfire and piston and/or valve damage can occur. If you need help having this repaired, a certified professional from YourMechanic can inspect the misfiring situation and have this addressed properly.