Misfire Cyl 1, running out of ideas

I've had this issue for a while now

Cold start in the morning, the car starts fine but as the RPM's drop, it starts shaking and will misfire. I can turn the car off and back on, then it idles a little rough (not as much as the first time) but once the temp gauge goes past the blue area, its fine... no rough idles or misfires

It's always cylinder 1 that misfires.

I've had new plugs in about a year ago, swapped coils... still misfires.. i put in a new coil on cyl 1, still misfires.

Replaced the intake boots, cleaned out the icv and throttle body, disa is fine but i did put in a new o ring on it.. had the shop do a smoke check (no vacum leaks). Had the shop check the sap lines, ccv was just replaced, all injectors cleaned and swapped around. the shop tech even went as far as replacing the fuel rail but that didnt fix it either.
compression tests came back fine, fuel pressure is fine too, put in a new fuel filter as well

Now he's telling me i need a new computer because thats the only thing thats left.

Code i get is P0301- misfire cylinder 1

I'm scratching my head here

any more ideas?

Could your plug wires be bad or you may still have a bad coil?

You might take to dealer to get them to diagnose. That's a lot cheaper than a new computer.

Originally Posted by Gold323Ci

Could your plug wires be bad or you may still have a bad coil?

You might take to dealer to get them to diagnose. That's a lot cheaper than a new computer.

These don't have traditional ignition wires and a distributor. Rather, there's an individual coil on each cylinder controlled by the computer.

OP: How are the connections on the cyl.1 coil? No fried wires or corroded connections? Start with the simple, obvious things before you delve into new DME's and all, and go from there.

Perhaps i should try some connection cleaner and double check the wires.

I also threw in a new MAF and car idles much better than before but still misfires.

The tech also told me that it runs too rich and he was getting those codes when it misfired however i only get the P0301 (unless my code reader does not catch the same codes or detailed codes).

The VCG was also replaced

Vanos seals is next (not sure if it will help but its due)

How did you clean your injectors?

Originally Posted by E46Mango

How did you clean your injectors?

The shop tech did.. and im sure he didnt have the tools to do a professional cleaning, but he did the most he could

before you go out of your way to clean injectors, try a compression test.

Originally Posted by zm323i

before you go out of your way to clean injectors, try a compression test.

He already did. Passed.

you talk about everything except plugs. you change those yet?

Originally Posted by E46Mango

you talk about everything except plugs. you change those yet?

Said he did last year.

Originally Posted by E46Mango

you talk about everything except plugs. you change those yet?

Originally Posted by too_desi

I've had new plugs in about a year ago,

It could have been a fouled plug. I say check the plug again

Wouldnt a bad plug cause problems aka misfires in this case, all the time?

It only happens when the engine is cold but once it warms up, its fine.. no misfires

I will swap the plugs around to see if it makes a difference.

too_desi,

Suggest you read the link in my signature below - Solve your misfires, lean codes, rough idle

MAF is not your issue, I see this has been replaced. I would cover all the basics with maintenance, but I see you are in Canada and I assume you temps are still pretty cold in the mornings there at this time of year>

I would be removing and inspecting the DISA, at a minimum replacing the DISA O-ring, info in the link I provided.

Also look carefully at the CCV lower oil return hose as well.

You could have intake gasket issues, but I would leave this to later, you need to make sure the "obvious" problems are resolved first.

Plugs, coils and coil boots, but coils and coil boot almost always give you problem at cold start but also under hard acceleration as well.

If you have the ability to also monitor and see the fuel trims, this may give you more insight as well.

What plugs did you use. And please say NGK...

Crankshaft Position Sensor???

Originally Posted by tonycajjo

Crankshaft Position Sensor???

Doubt that would cause a misfire on just one cylinder.

Originally Posted by JohnIBarr01

What plugs did you use. And please say NGK...

NGK

there, i said it

Originally Posted by JohnIBarr01

Doubt that would cause a misfire on just one cylinder.

dunno, prob not a true misfire, just reporting that as the code. dont crank errors always point at cyl 1?

I think the post count says it all!

don't change anything more my friend. your problem is lifters. everyone is trying help i know but it is pointless. everyone is forgetting that the problem is only at cold starts. i have the same problem exactly. you have to replace your hydraulic lifters.