Cyl 4 Idle Misfire Critique my current plan of action

[iv_05gt]

It's a 2005 LGT w/ 145k on it.

Infamous1 E-tune via Cobb Accessport

I've got a BNR 16g w/ IP&T oil line (19.5lbs tapers to 16lbs)

Replaced both OCV's

3" CNT catted DP

Invidia Q300 V3 catback

Stock Fueling (never touched)

IPR TMIC w/ MR Gasket to turbo

GFB 50/50 BPV open slightly to VTA.

Grimspeed EBCS

 

 

 

From what I've gathered from reading through the forums this is my plan of attack.

 

#1 Check the plug & gap to see what's going on in there.

(it was missing before I changed the plugs around 5k miles ago)

 

#2 Compression Test

 

#3 Leak down test

 

#4 Re-Check for vac leaks.

 

#5 Replace Intake - TGV gaskets & finally install new turbo inlet that i've been waiting to do.

 

I've come to figure the issue is any or combination of the following.

 

Bad intake - TGV gasket, Leaky Injector, or internal issue.

 

Am I missing anything?

 

Any/all input is appreciated.

[Max Capacity]

If it's just number 4, swap the coil with number 2 and se if the CEL follows it.

 

If no, swap the injectors between 4 and 2, see if the code follows.

 

If no, then do the compression test.

 

Unless you have a compression tester, then by all means give it a shot, it only takes a few minutes.

[xt2005bonbon]

if it's just number 4, swap the coil with number 2 and se if the cel follows it.

 

If no, swap the injectors between 4 and 2, see if the code follows.

 

If no, then do the compression test.

 

Unless you have a compression tester, then by all means give it a shot, it only takes a few minutes.

 

+1.

[jp233]

Yep. Swap coils.

 

Testing the injectors is really easy too, but not completely foolproof.

 

If it doesn't follow, then test the mechanicals (compression test doesnt really lie much). If it's good, then it's definitely electrical or a vac leak

[solo413]

I just had this same issue i took it in to agile auto in belair, md (nice shop, good people) they told me that my valves needed to be replaced after doing test and it was going to about 1800 with all the work they had to do.

 

I took it into subaru dealer by my house (matt slap subaru newark, de) they checked the car out gave me same diagnosis but told me they could do the work for 750 so i went with subaru dealer, they got the engine apart and realized i had a cracked block near the valve on cylinder 4. and it was going to be 2900 now but because there was some issue with this subaru of america stepped up and ate the cost for me and all i had to pay was 500 total. they replaced the small block engine all valves in the engine bay as well as fluids in the engine (except brakes) since then no problems with my subbie.

 

after many prayers and happy thoughts towards my subbie I am getting back on track with performance upgrades.

 

I hope this is not ur issue but just in case check out ur local subbie dealer they may be able to hook u up like mine did. best of luck with ur car bro!