Misfire code cylinder 8

[robmustang201528]

I can't win!!!!!. I haven't had the car back for more then a month. Did the break in period for a thousand miles. New stock short block, only making 10.5 pounds of boost at the most and now I have a misfire code. Took it the shop, they did a compression test on cylinder 8, it was like 100% comparied to cylinder 7 that read 200% .The most common code that pops up is cylinder 8 misfire but I've also gotten a random misfire code and a p0304 code as well. Shop thinks my injector went bad on cylinder 8 but I'm having a hard time beliving that. I have a set of ID 1000 in the car. The car doesn't show any signs of loss power, smoke, hesitation, skipping or anything. Car still drives normal. I don't understand why this keeps happening . MODS list. V7JT vortech, 18 intake, ID 1000 injectors, torque booster, boost controller, vmp BAP and lund tune. What is the problem?? What is causing the same issue I had. Has anybody had any issues with the 18 intake throwing misfire codes?

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[D98gt]

Have you pulled the plugs out to at least check them?

 

[robmustang201528]

Yeah shop said the plugs look good

 

[D98gt]

Have you ever had the injector's went through or even swapped them to see if it jumps? Doesn't cost much and isn't a bad idea especially if they've seen e85

 

[robmustang201528]

I haven't yet. Going to have the injectors flow tested some time next week. Injector have never seen E85

 

[robmustang201528]

What do you mean by jumps?

 

[TheHydro]

I believe he means to try moving the injector from cylinder 8 to another cylinder and see if that other cylinder now gets the the misfire code (jumps).

 

[F1scamp]

What would swapping injectors hope to fix if the compression numbers are already down 100psi in one cylinder? Dude. Sell the car and buy a Toyota.

 

[Grimace427]

What would swapping injectors hope to fix if the compression numbers are already down 100psi in one cylinder? Dude. Sell the car and buy a Toyota.

One would think if one cylinder had half compression you would have driveability issues plus smoke out the exhaust. OP says engine runs fine.

 

[robmustang201528]

No smoke, no hesitation, no skip, doesn't over heat, drives normal. Its F$@% weird. I wouldn't know there was a problem If the check engine light didn't come on. The second time this has happened. First time the cat got clogged and lost compression in cylinder 8. This time I have no cats on the car and I have the same issue. WTF smh

 

[robmustang201528]

This is all at idle. Does this look normal.

 

[Grimace427]

Yeah that looks fine.

 

[robmustang201528]

Yeah that looks fine.

Does that mean my injectors are working properly?

 

[Roush05]

they checked plugs, did they check coil packs?

 

[robmustang201528]

No they didnt check the coil packs. I'll have them do that next

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