Toyota Camry 2001:Any Ideas about Blinking Check engine Light and random Misfire CodeP0300

When an engine misfires, it can be fuel delivery related, spark related, and base engine related. You need the pinpoint tests for the code, p 0300 You can seek data and possible causes at enginecodes .com, the public libraries' auto database, or contact the emissions authority for advice about certified shops in your area. Since misfires can affect your tests when you get them, it behooves you to seek their help. They cannot charge you for unrelated repairs. they would perhaps recommend other things they find, but concentrate on the diagnosis. If you did your own guessing, you could spend money on unnecessary parts. It is less expensive to buy the testers and tools to do your research and see what your tests reveal. Often misfire codes are injection or distributor related. specific tests in these areas can prove you just need one injector or one part in your distributor, or one ignitor coil or one switch. Overheats can cause failures that are found during diassembly and inspection. For example an ignition part with a crack or temp related internal failure by short circuit or open circuit. Some code readers can give clues about inop injectors etc. The code reader can be had at the local parts store to observe all of its data rather than just a code. You have some things to do before any educated guesses beyond this can be of real help.

You might have a vacuum leak. Check the under hood decal for a vacuum diagram. Check all hoses for cracks disconnects and hardness. Sounds like you may have a LEAN misfire. Difficult to track down without special tools and equipment.

Thanks Mark, Here is what I have done sofar: -replaced Spark Plugs -replaced spark plug Wires -Removed the coils and measured the resistance between Terminals; they read 12.95 and 12.85 -Cleaned Idle control Valve -Removed all 4-injectors and cleaned them with pressurized carburator cleaner; connect a 9-volt battery and they all Spray -blow smoke into Vaccum lines and could not see any leak - I am going to do a cylinders compression Test

any other ideas on what else I can do to find the root cause of the Problem?

Can you see hairline cracks in the ignition coils ? what is the reading to the end when you run the second ignition coil test primary to secondary. how many ohms ? Have you at least a chilton manual ? Free, if you request it at the public library. Whose brand of spark plugs are you going to use and what part number? Is that part of the problem? Deposits on the old ones ? Next, what is your fuel pressure, rest pressure, and volume ? Harbor freight is an inexpensive place to find testers and supplies to make things that help.

A lean misfire can be considered tune up related. if you are behind on maintenance and have many hoses to contend with, concentrate on one at a time. cut sample segments to match up your part needs. The best emission hoses are at toyota. this solves your next repeat repair. A compression gauge is available at harbor freight, be sure the threaded end can reach into the cylinder head threaded spark plug holes.