The car went in for a tune up , afterwards I started noticing that it ran rough and was getting codes.  Finally have it down to one code that pops up repeatedly which is #4 cylinder misfire .  I replaced the plugs again , and moved plug wires around and even put a new ignition coil on.  Still getting the same code and I am wondering if it might be the injector starting to go bad, I have 259k on this engine and it doesn't use oil or run hot. The car will sometimes go 80 miles or so before the check engine light comes on and other times just a few miles and it comes on .  The engine is a 1996 2.5l and has run fine before all this started.

whats the code?

We're the plugs oil fouled? What did the plug electrode look like? Have you done a compression check?

Maybe a vacuum line in the wrong place/not hooked up?

The plugs look great , compression is good on all cylinders, one of the earlier codes said that it was an injector, that is the only thing I haven't tried yet.  I have never gotten that code since changing out all the plugs again. 

the code is p 0304.

HI,

Move or replace that injector, and see what happens. Otherwise, I'd get a leak down test to see how the valves are doing. These 2.5's are due for valve adjustments every 105K miles, so you may be (over) due, and if ignored for too long a valve can get burned (literally).

 

Good luck,

TD

thank you , that's the one thing I haven't done, I was going to go ahead and replace the injector since that code came up once, might as well adjust the valves also.

Make sure the injector is plugged in all the way. Sometimes they get unplugged to get a little easier access to the spark plug. Might not be clicked down all the way or there could be crud in the terminals causing a poor connection.

 

Typically misfire problems are spark related but it sounds like you've swapped enough ignition parts to rule that out.

Installing plugs in a EJ25D isn't easy, very tight squeeze. its possible you may have cracked a plug installing them, I know I did when I changed my plugs.

what was done on the tune-up and what brand parts were used?

New plugs , new wires they used bosch double platinum plugs and a good wire set, since then I have changed out the plugs twice and am still getting a P0304 code which says it is #4 cylinder misfire, the only thing I haven't done is change out the injector, and I did get a code one time that was listed as an injector, that was several months ago , and now am wondering if the injector is starting to fail.

Were they the single electrode double platinum or double electrode platinum +2 plugs?

 

The +2 double electrode plugs cause issues in these.

No they were the single electrode, and I have changed them out , now I am looking at the fuel injector for number 4 cylinder and when I messed with it yesterday the code came on right away.  How hard is it to replace the injector in these engines and is there a difference between OEM and aftermarket injectors

loosen fuel rail and pop them in and out, pretty easy really.

 

they rarely have issues/fail so i doubt you'll see a statistically meaningful sample size on various options.

 

witchhunter and RC Engineering can pre and post test and rebuild injectors (the former being the cheaper)

used is a good option with how rarely they have issues.

unsure about aftermarket, given how easy they are to swap and if there's a compelling reason i'd probably try them.

if wiggling it caused issues- may want to verify it's not hte harness or wiring before messing with the injector?

Good point,I was thinking that perhaps the wiring is in need of being closely looked at,I'm sure these are the original injectors so it would stand that perhaps my wiring has detoritiated.

these injectors dont fail that often.. that would be the last thing i replace.  If you can get a whole intake with injectors from a junkyard i would grab that and install. With this you will cover the injector and the wiring.  

That is an option I never thought of, I will check around the bone yards and see if I can find one.