Hey yall, as of last month I am the proud owner of a 1999 3.4 L limited 4runner with about 240,000 miles. I bought her for just $500 with some minimal front end damage that I have been gradually fixing. There is one problem that I have, since I got her running shes throwing a P0303 code, therefore I changed the spark plugs to NGKs,changed all the wires, and all three coils. After all this the code still continues BUT only when I drive it, the CEL blinks for a short amount of time then will go away when I slow down or come to a stop and will NOT stay lit. When I drive her she feels fine apart from some slight vibration in very low RPM, she still accelerates fine and is NOT making any weird noises or spewing smoke from the exhaust, the oil looks fine. I figured that since the car has been sitting for who knows how long I'd add some fuel injector cleaner, this did not solve the code either. I did a sound check of fuel injector and they do seem to be "clicking", so at this point I am out of ideas and would like to see if anyone can help out. Thanks!

P.S. sorry for typing so much just wanted to get it all in there.

Cel flashing = unburned fuel in the cats. you can clean the maf and see if that helps. ohm out the injectors I think it should be around 13.6 ohms will have to check the fsm to be accurate. sometimes the injectors malfunction even when they are within specs. In my case after troubke shooting a bunch, I swapped the injector to another slot in the fuel rail and the misfire jumped so I knew that I needed a new oem injector.

So I cleaned out the MAF with cleaner, and just bought a multimeter to check the ohms, I'll keep you posted and thank you for your help. I think another thing I might as well do it change the spark plug O rings and gasket cover seals since there is some oil leakage, while I'm there I might as well just change the fuel injectors. I just wanted to make sure the engine isnt completely trashed.