Hi every one! I got 04 Z which has run 75k miles.when i speed the car after 4-5k rpm the car goes very slow. These happens only some times.The car shivers little bit also.its a stock car.
Could some one tell me any idea wat will be the problem.

 

any recent spark plug change? could be loose plug or bad plug.

 

checked the spark plugs, all in perfect condition, still its the same

 

Can you describe the condition in more detail?

Are you getting any Check Engine Lights?

When does the shaking occur? It could be a misfire.

Are your coil packs securely attached to the spark plugs?
Are the sensors attached to the coils?
Do you have an aftermarket intake?
Is the plug securely attached to your MAF?
Auto or 6MT?

 

Dar z no check engine light. dar is slight vibration and misfire in between wen i drive on high rpm,coil pack and spark plugs removed and reconnected it properly. I have injen intake system and it is 6mt

 

after 4k rpm the car does not move fast as it use to move, it goes very slow after 4k rpm

 

How about replacing the plugs, check the MAF, and cats.

 

Clean out your MAF and try the stock intake for a bit.

How long has this been going on? Is it possible the intake just got wet?