been trying to figure out a p0304!

[oxyhydro]

Ok well i have had this misfire pretty much since i got the car at around 175k miles, it has 212k at the moment. At first it would be like once a month ill see that code an goes away in 30mins to 1hr but since around 205k miles its been more frequent an seems like it pops up at start up most of the time, sometimes i wont see it for weeks an other times it will pop up every other day! So first i changed the plugs with stock delco ones (you can see the old ones in this http://www.saturnfans.com/forums/sho...=208354&page=3 ). Then after a couple weeks started to still get the cylinder 4 misfire, so i just did a bunch of searching an only things i could really find is icm, coilpack, injectors, ecm ect... can cause misfires, so after a month or so it the code would pop up here sn there an then i got a p0304, p0300(multi misfire), p1574 (stop lamp switch circuit ) witch at the time i was by advance auto an they read it an sed it was injector 5 circuit (witch i dont have a 5th injector witch was weird) but i searched it an thats what i found

So i just finally went ahead sn got a new icm an coilpack with lifetime warranty witch i didnt really wana do an i thought i fixed the problem but then the p0304 came back in almost a month, so i did more searching an i found a bulletin# 050604005 on the 05 ion coupe an it sed that the p1574 an mifires can be related an sed something about reprogramming the ecm but i have never heard of this problem an cant find nothing on here about it, in the last week i have got a misfire at start up every other day, sometimes when i first start the car an sometimes when i have already been driving it recently an still warmed up an shows at start

I checked my plugs the other day an they have around 8k miles on them an 1,2 an 3 all where pink on the insulation tip an the 4th was normal white, actually the 4th looked the best to me (pics here http://www.saturnfans.com/forums/sho...=209353&page=2 ) i dont think its the injector causing thr misfire cuz you should be able to tell on the 4th plug, the pink i only can think of fuel additives but i havent put nothing in since months before new plugs were put in an i only use shell gas witch it could be from that but never heard of it! I dont have that much experience on injectors an i no nothing on ecm's, so hoe should i go about this? I dont wanna just throw money at it to see if it will work!

[Samtherecordman]

Originally Posted by oxyhydro

Ok well i have had this misfire pretty much since i got the car at around 175k miles, it has 212k at the moment. At first it would be like once a month ill see that code an goes away in 30mins to 1hr but since around 205k miles its been more frequent an seems like it pops up at start up most of the time, sometimes i wont see it for weeks an other times it will pop up every other day! So first i changed the plugs with stock delco ones (you can see the old ones in this http://www.saturnfans.com/forums/sho...=208354&page=3 ). Then after a couple weeks started to still get the cylinder 4 misfire, so i just did a bunch of searching an only things i could really find is icm, coilpack, injectors, ecm ect... can cause misfires, so after a month or so it the code would pop up here sn there an then i got a p0304, p0300(multi misfire), p1574 (stop lamp switch circuit ) witch at the time i was by advance auto an they read it an sed it was injector 5 circuit (witch i dont have a 5th injector witch was weird) but i searched it an thats what i found

So i just finally went ahead sn got a new icm an coilpack with lifetime warranty witch i didnt really wana do an i thought i fixed the problem but then the p0304 came back in almost a month, so i did more searching an i found a bulletin# 050604005 on the 05 ion coupe an it sed that the p1574 an mifires can be related an sed something about reprogramming the ecm but i have never heard of this problem an cant find nothing on here about it, in the last week i have got a misfire at start up every other day, sometimes when i first start the car an sometimes when i have already been driving it recently an still warmed up an shows at start

I checked my plugs the other day an they have around 8k miles on them an 1,2 an 3 all where pink on the insulation tip an the 4th was normal white, actually the 4th looked the best to me (pics here http://www.saturnfans.com/forums/sho...=209353&page=2 ) i dont think its the injector causing thr misfire cuz you should be able to tell on the 4th plug, the pink i only can think of fuel additives but i havent put nothing in since months before new plugs were put in an i only use shell gas witch it could be from that but never heard of it! I dont have that much experience on injectors an i no nothing on ecm's, so hoe should i go about this? I dont wanna just throw money at it to see if it will work!

i bet you you still did not figure out what this one was all bout......... yes its a miss fire, but your still under the hood not at your desk....

[bern]

With all spark plugs remove first, Preform a compression test

Do you feel the misfire at idle? at fast idle?

[oxyhydro]

Originally Posted by bern

With all spark plugs remove first, Preform a compression test

Do you feel the misfire at idle? at fast idle?

Well i haven't had a misfire in almost 2 months so it mite be fine but last time i thought that i ended up getting a code, the idle seems to stay fine, it just vibrates alil sometime siting at a redlight, but i noticed i would get a misfire code when i start the car an not during driving, i think when im like going short distances an turning off the car to go in a store real quick then going to another store, so its like when i drive store distances an restarting the car soon after i turned it off alot

The car actually runs pretty good over then the roght vibration (idle doesnt change) at lights. I was having a jerk when going up the start of a incline where i would slowly accelerate but dont think its cuz of shifting gears an never really saw the idle change during the jerk, an i don't think i have ever got a code during that jerk or soon after either but it could be related to the misfire cuz i havent felt that in awhile either, it seems like the harder i am on the car the better it runs but not sure why

[bern]

If you have one or more valves starting to have poor sealing to the valve seats: 1) Will be more noticeable at low engine and vehicle speed, like backing out of a driveway 2) Compression test will be slightly low. 3) a leak down test will show the failure more than a compression test.

As a valve becomes burned 1) you will always feel a rough idle and feel steady misfire when accelerating. 2) will be low compression 3) leak down will be high. 4) a misfire from ignition failure can be steady or random.

[oxyhydro]

Ok thanks, before i cleaned me tb a few months ago i would back down this persons driveway that a hill so i would pretty much hold the brake the whole time an while doing that my idle would jump a few hundred back an forth without me hitting the gas an only the brake but since i vleaned my tb that got fixed completely but it didnt help much for the redlight stops.

But can any of those problems you listed just go away for along time? An also i have only ever had p0304 an 1 time i had a p0300 am p1574 around the same time, i have tryied to take the fuel rail off a couple months ago but 1 of the bolts wher broken, it seemed like the original owner broke it an sat it back so it looked fine, i tried using a screw extractor but i actually broke it luckily i was able to get that out, i wanted to switch injectors an also see what they looked like

[tooner98321]

For all of you that may be dealing with this issue.

2001 Saturn SL2 DOHC 275000 miles.

P0304 Code. Cylinder 4 Misfire detected.
"Service Engine Soon" light illuminated.

Rough idle and misfire heard at exhaust.

I did the following:

1. Cleaned EGR valve. No help.
2. Blocked EGR with blanking
plate. No help.
3. Replaced spark plugs and wire set. No help.
4. Checked compression.
#1-200, #2-210, #3-190, #4-200. Looks good.
5. Used carburetor spray cleaner and checked
intake manifold for leaks with car running at idle.
Manifold checked good.
6. Checked fuel injectors with carburetor spray cleaner at fuel rail and
intake manifold. Found #2 and #3 injector o rings leaking at
intake manifold.
7. Installed reconditioned injector set.

Problem fixed.

[Bill Murray]

Great post, tooner.
Good work, thanks for info