manicmechanic

The car is a 2003 ex, 5 speed. Keeps throwing misfire codes for all cylinders. p0300,301,302,303,304. Checked compression most cylinders were at 150, the lowest was at 145. Checked valve timing, timing is on. Part that have been replaced. All Honda parts installed. Spark plugs all 4, all 4 coil packs and all 4 fuel injectors. After replacing all of these codes still come back within 2 to 4 miles of driving. It will start off with having cylinder 2 and 3 in pending, then further down the road the rest will come back. I have noticed that when driving sometimes at low rpms around 1500 and 2200 it will sometimes stumble, but it doesn't do this all the time. Coolant doesn't look discolored like exhaust gases getting into it. Is it possible that the headgasket is bad? I would think so with compression numbers that I have gotten. Maybe ecu?? I am at a loss of what to do next.

lazlong

Check for proper fuel pressure. It should be about 40-45 psi.

Check the EGR for proper function: After removing the EGR, check that the plunger moves freely when you push it with your finger. If it doesn't move freely, clean or replace the EGR and clean the engine passage all the way to the intake plenum. Yes, you need to remove the plenum and throttlebody to fully clean the passage.

manicmechanic

The egr valve was cleaned. I am sure that the plunger did move freely. I can't remember, because that's one of the first things that I tried. As for the passage I can clean that out too. And when I do I will recheck the egr plunger. I really don't think it's a fuel issue but will look into that as well. I think I need to do a compression check with the engine at operating temperature. Because that is when the problem starts, and while at it a leak down test. Because as soon as it gets to operating temp is when the misfire starts. Cylinder 2 and 3 come right back on. It takes a lot longer for the others to come back. I am thinking maybe the head maybe warped and or the head gasket maybe the issue. The only compression check that I did is when the engine was cold.

davetheman81

Check fuel pressure and clean fuel

gmcuajo1

I bet to an intermittent TDC sensor fail (top dead center). This is the sensor that reads timing from the camshaft.

It starts giving you that type of misfire codes in all cylinders. After some time of repeating that, the ECU start protecting the engine and doesn't let the engine go over 3,000rpm+. Then it throw the code for the TDC itself.

The TDC cost around $45-85 depending on where you are.

Remember to replace all the spark plug.

If you have this problem, not rev over 3,000rpm, stop and turn off the engine, remove the 10A ECU fuse for 10 secs, put it back, and start the engine again.