P0303 cylinder 3 miss fire on start up

Hi everyone, I have a 3.4 4x4 I'm still pretty new to TW so my bad if there's already a thread on this. I've just been doing some searching on this code over the past month and I keep having trouble with this chronic code. I replace the spark plugs, cleaned the injectors and replaced the spark plug wires. Yet this code keeps coming back, what I have noticed is that it only misfires when I start the motor, only happens for at longest a minute then smooths out and doesn't misfire anymore, anyone ran into this problem before and able to fix it? Any help/knowledge is appreciated

 

How may miles?
drive the truck to get to operating temp..park it over night. Next day remove spark plug #3 and try to peek into the cylinder and see if there are small amount of coolant?
If there is little traces of coolant that will cause your slight misfire on cold start.
Motor will need head gaskets

 

I currently have 90106 on it, just did the timing belt myself

 

did u have misfire issues after t-belt service?

 

No this has happened before I replaced the timing belt, but it is the first time in few weeks it's happened

 

last time I used the chevron injector cleaner you mix with a full tank of gas and it went away until now

 

couod you swap injector 3 to cylinder 1 and see if problem move to cylinder 1

 

Drive you truck to the nearest convenient store and buy a fountain drink. Pickup a few extra straws. They have to be the ones with paper wrapping. Drive home and watch a good movie then call it a night.
Now back to the straws.
In the morning crank you truck over just until it starts to run on its own. Then shut it off. You only want it to run for a second or two. Pull #3 plug and the other plug that shares the coil. Dip the straw paper and all into the spark plug hole and rub around on the piston. You may have to turn the motor to reach the piston and not lose your straw. When you pull it out I bet its wet from fuel =Leaking injector. If it was water the truck would be overheating.

 

Thank you I'll try that tomorrow

 

If you have any extra straws. Make spitballs and blow them at this guy @Dalandser ...

 

So this is what happens when I don't tag you in a thread before you get to it yourself eh?

I might have some questions for you...



Starting tomorrow. Let's see how much I get to do before the real world sets in and my vacation ends.

 

Ok guys I finally got around to checking for gas in the cylinder and I don't think I found any, just oil, but here's some info when I changed the spark plug earlier this summer. All the spark plugs came out nice and easy, but then cylinder three was stuck and I ended up using a breaker bar to get it out. I also re threaded the spark plug hole and used a set up my dad had thought up to catch the shavings so they wouldn't end up in the cylinder and then I put the new spark in. This time when I was checking for gas it came out way easier but still wasn't smooth. Thoughts? Could it be a vacuum line not sealing correctly?

 

Here's a picture of the new spark plug I put in a couple months ago, is it supposed to be wet like this?

 

This is a spark plug from a different cylinder. Noticed, not as oily/dirty, what does this mean?

 

Dude I've got the SAME prob
Changed plugs-wires did the chevron injec cleaner a bunch of times

In the morning when i start it it will miss fire for 30 sec- 1 min then clear up and run great all day. i'm not using any coolant or oil and no overheating issues.
I'm Supercharged so I have different plugs.

I still have not figured it out I'm thinking a leaky injector might be the cause..
Jerry

 

You may have blow by on that cylinder 3. It where the piston rings can't scraped excess oil from the cylinder wall on the down stroke.
Check your intake. Manifold if there a puddle of oil?

You may have a to do a cylinder leak down test on all Cylinders. Test will give an idea how well that cylinder is sealing

 

Would a compression test do anything for me? I have a compression tester

 

Yes that will work also. Have a battery jumper on or if the battery in good condition is OK. And keep the throttle body wide. Open throttle

 

I'm still leaning to a leaking injector. Did the plug smell of raw fuel?

 

No it smelled like the fresh oil I put in about 100 miles ago