code p0300 keep coming up on my x-type. i have changed the spark plugs, coils, oil an fuel filter within the last 2 months. i have noticed my brake booster linkage with air manifold have corroded. thats the reason for the stiff brakes. today is sunday an dealership isnt open.. ima have to drive a hour to dealer should i think about picking up some more parts while there to eliminate p0300???

 

jayes, first off, welcome to the Forums. I think you will find a lot of useful information here. But, we do ask a simple thing from you though. Please stop by the New Member Section and introduce yourself. You will find that we are a friendly bunch and we like to get to know one another. Besides, this will also give you a chance to meet the movers and shakers of the site. Then, sit back, get yourself a cup of joe and enjoy. Lots of good information here.

As for your problem. I would first start with looking inside the engine bay at the front left corner of the engine. You should see where 6 wires are grounded to the engine block. These wires are the ground wires for the ignition coils. Remove the bolt that is there, clean up the surfaces with a little bit of 400 grit sand paper or a greenie scouring pad to restore the surfaces to a bright shiny metal surface again. Do not forget to do the bolt and mounting surface of the engine block too.

Next, what I want you to do is to go out and start your car after letting it sit all night and get a feeling for how long it takes for the motor to catch and start (going immediately from the OFF position to the START position with no pauses). Now, turn the car off and wait a minute. This time, turn the key from OFF to RUN, wait 5 seconds, then turn to the START position, noting the time it takes for the motor to start. Is the two times about the same or does the first start take a lot longer? If it takes a lot longer, you may be having a fuel pump starting to fail on you. At this point, you need to get your fuel system pressure checked (if you need the pressures, let me know).

The final thing, if you are like most people, you use the same brand gas most of the time. For a tank full or two, use a different brand. Different gas stations use different detergent packages in their fuel and by switching brands, you may clear up your injectors, leading to a better spray of the fuel (and therefore no random misfires). I find that I use Wawa for most of my fill ups, but when I switch over to Sunoco for that tank or two, the car runs a little bit better afterwards.

 

On a side note, are you following the recommendation for using premium fuel or are you using a lower grade gas? That can also possibly lead to what you are seeing. Some people have found that their cars will work fine on the lower grade gasolines, others have nothing but issues. Just making sure we have a known baseline for what is going on with the car.

 

thank you i havent yet took the ignition coils ground off yet but my fuel pump is working properly to my knowledge i hear it cutting on each time before i turn it over. i only put 93 in my car i do switch fuels companys majority of the time bp or wilcos gas. i think i need to look into the fuel regulator. whats the pressure the fuel should be at ?

 

jayes, when looking at the fuel pressure, with the engine off but the keys in the RUN position, the fuel pressure should be in the 40-50 psi range (closer to 50 psi). With the engine running, the fuel pressure should be in the 30-40 psi range (closer to 40 psi). If the fuel pump is starting to go, you will see the fuel pressure down near the bottom of the range, if not outside of it. Another check that you can do is to let the car sit over night and then when you go to start it, roll the ignition key from OFF straight to START (no pause in the RUN position) and get a feeling for how long it takes for the engine to start. Then turn the engine off. This time, turn the key from OFF to RUN, wait about 5 seconds and then finally roll the key to the RUN position. Note the time it takes for the engine to start. if there is a significant difference, a sign that your fuel pump is starting to go.