i have an 02 accord with the 4 cyl vtec. i bought it a few days ago and it was running fine, now that i have drove it for an entire day i noticed a few problems so i had autozone read some codes for me and it came back as cyl 1,3,4 were misfiring. so i changed the plugs and wires and inspected the distributor cap which seems to be fine. i used ngk plat. plugs and duralast wires, also the guy at the counter sold me lucas injector cleaner which i put in and the tank is empty as of today and im still having problems. if i let the car attempt to idle on its own it will drop to 400rpm and will start to make the car shake a little, i tap on the gas and it will idle high around 1700, but only to go back down below 1000rpm. it seems as if the computer cannot make up its mind. also i took some slack out of the throttle cables also please let me know if you have any advice it will be greatly appreciated

 

Make sure there is some slack in that cable, so the throttle body is not slightly open. You may want to clean both sides of the throttle plate and the bore of the throttle body with some throttle body cleaner.

Also, when the engine is cold, you should check the coolant level in the radiator. The level should be all the way to the top.

 

i took my car to autozone and had them pull some codes and came back with
p1259-Air fuel metering
p0420-EGR
p0301-Cyl 1 misfire
p0302-Cyl 2 misfire
p0304-Cyl 4 misfire
p0300-Random misfire
p1399 (not sure what this one was)

mechanic said somthing about an exhaust valve being clogged inside the engine and this would potentially cause the misfiring. when i changed my plugs the tips where a burnt white color. if this info helps out any more please leave a comment thanks

 

I have the 1250 as a vtec issue? Is or has the oil been low?

The 0420 is a cat below threshold, O2 maybe-TEST.

For the others, clogged egr ports or valve "might" be an issue. Did they reset/clear the codes.

I don;t see the 1399 listed either?? Is see a 1359, a reach using the number given- that is for the crank position sensor....which could explain a lot...misfires, ect.

 

i took my car to a honda mechanic (guys house not a dealership) and he did some investigating, first he took the airbox off and cleaned the throttle body which was pretty dirty, added some oil and started it up to read the codes again, came up with the p1399 code which was unknown. mechanic then checked the plugs finding cyl 2's plug different from the others (all are burning white except cyl 2) so he checked the compression in cyl 2 and came up with 65ish and cly 1 was at 135ish..in all the mechanic said its possibly a intake or exhaust valve not functioning so he would have to pull the head and send it to a machine shop to get any valves "pressed" (and he wasnt sure on a price for this option). or my other option was to exchange the head from my engine with one of the heads off an engine in his shop (identicle engines) this option would be around 600 if everything went as planned.

so does this seem like the problem or should i expect something else to be wrong? and does the head actually have to get sent out to a machine shop for the valves to be installed? any other input is greatly appreciated

 

The mechanic should do a leakdown test on the cylinder with low compression. It will tell you that compression leak is due to exhaust valve, intake valve, head gasket, or piston rings.

If you have a bad valve, the head will need to be sent to a machine shop to mill the head so it is flat. They will also replace burned valves, guides, etc.

If the problem is with the lower end, then you should consider having a used engine installed.