Car is not running right. Rough idle and misfiring under acceleration.

Wilson2608

Okay I’ve checked a lot of things since last posting. Not fuel pump as i checked it with a gauge, it could be a injector I’ll double check that next. Negative cable is good, spark plugs were not bad either.

I’m really starting to think it’s my cats. They are Z1 Motorsport cats and I’ve had them for about 40k miles. The problem is so inconsistent it’s hard to diagnose. Today i hopped in and fully accelerated and i had like maybe half the power and the engine sounded really muffled almost like i had an exhaust leak but it was quiet( if that makes sense). Stopped the car went to class then came out an hour later, full throttled the car with no problems at all.

I’ll try to take a video next time it happens and upload it. Thanks for everyone’s input so far.

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Stillen G3, z1 Intake Manifold, Stillen Headers, Z1 HFC's, Stillen Catback. 330whp 267 ft- lbs tuned at Z1 motorsports.

Quicksilvers

Clogged up high flow catalytic converters is another possibility to your symptoms your are experiencing with your Z. How knows what vendor Z1 is using to supply their high flow catalytic converters and how good of quality they are?

Wilson2608

I’m going to lift the car up this weekend and check to see if that’s the problem. I guess I’ll have someone rev the car at about 2200 rpm and test the airflow coming out of the exhaust pipe (right off of the cats).

Anyone have any other ideas as to how to test a clogged cat?

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Stillen G3, z1 Intake Manifold, Stillen Headers, Z1 HFC's, Stillen Catback. 330whp 267 ft- lbs tuned at Z1 motorsports.

Rusty

Google is your friend.

https://www.google.com/search?q=how+...hrome&ie=UTF-8

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浪人 - 殺し屋
"The Difficult Anytime, The Impossible By Appointment Only"
http://www.the370z.com/members-370z-...o-journal.html

Wilson2608

Thanks everyone I’ll check into that this weekend. I’m leaning toward it being the cats simply because of how bad my car is running and it will not throw a check engine light. If i have half the power and my car is running like crap it should throw a code. My cat codes have been permanently disabled through uprev.

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Stillen G3, z1 Intake Manifold, Stillen Headers, Z1 HFC's, Stillen Catback. 330whp 267 ft- lbs tuned at Z1 motorsports.

Wilson2608

Sadly it is not the cats i checked them today. I’ll keep looking for the problem it’ll turn up eventually lol. Thanks for the reply’s

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Stillen G3, z1 Intake Manifold, Stillen Headers, Z1 HFC's, Stillen Catback. 330whp 267 ft- lbs tuned at Z1 motorsports.

Wilson2608

So here we are, the 370z still is running like ****. I took a break and focused on the 300zx but now I need to get back to it.

What I have tested:
Fuel pump
Injectors
Coil packs
Spark plugs are good
Air filters replaced
MAF and TB cleaned
PCV valves cleaned.
Checked for vacuum leaks
Replaced valve cover and spark plug gaskets( though for sure that would fix it as there was oil alll over spark plugs )

As i stated before I checked the spark plugs, they look fine and they have about 55k miles on them.

I’m making this post in hopes anyone has any other tips ideas. I’m kinda at my last ditch effort here. Gunna get my boost leak tester from 300zx to be 100% sure there’s no air leaks.

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Stillen G3, z1 Intake Manifold, Stillen Headers, Z1 HFC's, Stillen Catback. 330whp 267 ft- lbs tuned at Z1 motorsports.