0303 code

95 taco 3.4 eng. starting to think an ejector on #3 as is missing a little, on start up, now with ck engine light. Started looking around and found this little valve I can not identify. Hose goes to throttle body. Well this plastic cap was loose, and can't get it seated. Down inside is a pin with a spring and a number 708 stamped on the bottom. So with this brown plastic elbow being not seated, could this be the cause of my misfire? will try to upload pic off iPhone. Thx. Dm

 

Whatever valve this is, the rubber boot down towards where it sits on the metal, appears to be brittle and has a crack all the way around it. Doesn't look like there is a way to snap this cap back over this. Thx for any help. DM

 

That's the PCV valve. It has a grommet that you can buy separately. Might as well buy them both and replace since you're right there. No, this won't cause a misfire. PCV valve just makes sure the engine can expel any extra pressure built up without allowing any outside air to get in the engine. Do a proper tune-up first and see if that rids the CEL.

 

Ok, so question on the coil pack. Does this unit also deliver energy to a plug on opposite side of engine, or is it just for plug #3? I will look at this closer later. What I have is a slight miss on start, then the miss corrects itself. Only happens (as of now) within the 1st minute. I'm guessing injector. 212K miles and a shop had already replaced one 3 years ago. I could throw a new coil pack on it just to check it (and return it if it don't fix the problem) The wires and plugs are fairly new. What is your thoughts? Oh, and I could ohm the injector, but wouldn't it be difficult to decipher if it were good or bad, due to the problem being intermittent? Thx DM

 

Replaced pcv valve and grommet. Started engine and no miss. But it is intermittent anyway. So took a long screwdriver and listened to #3 injector and sounded normal. Turned off lights and looked for any spark and arc and nothing. So unsure what is causing miss on start up sometimes. Sucks when there isn't a hard fault.

 

you posted your results as i was typing this

Yes, your coils send spark to the plugs on the other side of the engine. .

auto parts stores will NOT return electrical items. don't buy a coil pack for testing. you're better off swapping 2 of your own coil packs and seeing how things turn out.

if your just getting a misfire on cyl 3, where a coil is, it really sounds like just the coil boot, try changing just that. It should just pop right off if it looks like the one in the link. and new boots like this come with the new springs that make the connection between the coil itself and the plug.

the spring is probably what the real culprit is by the sound of things.

cylinder 3 should be the middle coil

 

other possibility could be the spark plug wasn't properly installed or gapped.

 

being that it only happens on start, and normally after been sitting a day or 2 and only lasts for 10-20 seconds is what getting me. Gut is injector, whether failing solenoid or dirty. I may try to reach in there and ohm it. I've read where have the open air leak, which I did with the pcv fail broken, could have caused it. I'll start it up tonight and see if the miss is back. I did reset the ck eng light.

 

Does the CEL stay on or or it goes away after the minute or so of rough idle? With the code you have i would start with a new spark plug first. I doubt it's a coil or it would be missing on two cylinders. I would also recommend finding a shop with a higher end reader as they will usually tell you more about what's going. My friends Matco OBD reader told me exactly what was wrong when my 02 sensor capped out. It told us the heater voltage on the sensor was lower than it should be.

 

After changing pcv valve I've started it 3 days in a row and no miss. Knock on wood but I think that big air leak was it.

 

has the mis back. only on start up and just for a few seconds. will change fuel filter and run some lucas fuel treatment through it.