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[craigd853]

Hello all, I have a 2010 camaro since new with an edelbrock supercharger on it. Janetty tuned with ID 850 injectors, headers and bigger fuel pump. I am having an issue that just started yesterday. When under a load and high rpm cars #8 cylinder is misfiring. I just put NGK plugs in it last year with brand new morroso 8mm wires. I have swapped out the coil and still have the misfire. I pulled the plug and it looks good and the wire is in great shape. I am an L99 and still have the original lifters and rocker arms in the engine. I am still going to swap out the plug and then the wire to see if there is any difference.Also if need be I will do a compression check to see if there is a compression problem if the plug wire or plug does not resolve my issue. I do not have a rough idle and when the car is in park with no load on the engine and when you rev it up it does not misfire. Has any one experience a possible floating valve do to a weak lifter. I know the lifters that come with the L99 are weak by nature as well as the needle bearings in the rocker arms. I don't beat on my car and it is not an every day driver as it sits in the garage most of the time. Just curious if anyone else who was boosted had any issues with their stock lifters going bad or being weak. I am running 9lbs of boost and have never had any issues with the car until now. Tune and supercharger have been on the car for almost 4 years with the same tune. Suggestions? Thanks in advance.

[Greenhornet2]

I'd swap the injector to another cylinder as well to rule that out. When you pull the plug I'd do a compression test, no reason not to. That will tell you a lot.

[craigd853]

Originally Posted by Greenhornet2

I'd swap the injector to another cylinder as well to rule that out. When you pull the plug I'd do a compression test, no reason not to. That will tell you a lot.

Yes definitely, thanks

[JANNETTYRACING]

Originally Posted by craigd853

Hello all, I have a 2010 camaro since new with an edelbrock supercharger on it. Janetty tuned with ID 850 injectors, headers and bigger fuel pump. I am having an issue that just started yesterday. When under a load and high rpm cars #8 cylinder is misfiring. I just put NGK plugs in it last year with brand new morroso 8mm wires. I have swapped out the coil and still have the misfire. I pulled the plug and it looks good and the wire is in great shape. I am an L99 and still have the original lifters and rocker arms in the engine. I am still going to swap out the plug and then the wire to see if there is any difference.Also if need be I will do a compression check to see if there is a compression problem if the plug wire or plug does not resolve my issue. I do not have a rough idle and when the car is in park with no load on the engine and when you rev it up it does not misfire. Has any one experience a possible floating valve do to a weak lifter. I know the lifters that come with the L99 are weak by nature as well as the needle bearings in the rocker arms. I don't beat on my car and it is not an every day driver as it sits in the garage most of the time. Just curious if anyone else who was boosted had any issues with their stock lifters going bad or being weak. I am running 9lbs of boost and have never had any issues with the car until now. Tune and supercharger have been on the car for almost 4 years with the same tune. Suggestions? Thanks in advance.

Thank you for your business,

It is not clear who you are but if engine is all stock I would be looking at Valve springs and possibly a bent valve.

Ted.

[RobZL1]

You mention checking the plug- did you verify the gap is still small enough? I change my plugs every year to prevent gaptosis. It will grow over time with boost, especially. If it's fine except in boost /high load, it might be gapped up in the 0.050"+ range. This could cause misfire only under boost.

[craigd853]

Originally Posted by JANNETTYRACING

Thank you for your business,

It is not clear who you are but if engine is all stock I would be looking at Valve springs and possibly a bent valve.

Ted.

Well Ted I hope your wrong buddy but if your not you will be getting a call from me for your rough idle cam along with the valve springs and accompanying mods. LOL

[craigd853]

Originally Posted by RobZL1

You mention checking the plug- did you verify the gap is still small enough? I change my plugs every year to prevent gaptosis. It will grow over time with boost, especially. If it's fine except in boost /high load, it might be gapped up in the 0.050"+ range. This could cause misfire only under boost.

Thanks Rob I will look into that as well.

[JANNETTYRACING]

Originally Posted by craigd853

Well Ted I hope your wrong buddy but if your not you will be getting a call from me for your rough idle cam along with the valve springs and accompanying mods. LOL

These cars are getting older and stock valve spring failures are becoming more common so I would pull the valve covers right away.

When the valve spring breaks the valve will come in contact with the piston and bend slightly.

A leak down test will verify if or not you have a bent valve.

I have good used heads available as well.