Causes of loss of top end power.
Discussion
I drive a 1.6l MIVEC engined mitsubishi, it's done 135k but is nice and pokey, generally.
The car has been fully serviced (literally all service items replaced), but seems to suffer from a loss in top end power. It is really sluggish accelerating from 80mph and beyond (on a private road). The MIVEC is engaging at 5k rpm in all gears as it should, and the car pulls really well to the redline in all other gears. Whatever the problem is, the wind resistance and lower power of 5th seem to be highlighting this power issue.
The car will be going on a rolling road, but not until the spring, in the meantime I figure it's worth trying to diagnose the issue if possible.
The car is JDM, but it's definitely not the limiter kicking in (speed too low). RPM at certain gears has been cross referenced with another car, so it's got the correct gearbox. Front caliper had been binding, but this has been fixed and doesn't seem to be a contributing factor. all other calipers seem fine.
it's due to have the valve clearances adjusted as these need doing, but i wouldn't expect that to cause such a drop in performance.
My initial thoughts are fuel system issue, or something being blocked in the exhaust somewhere. Any thoughts?
The car has been fully serviced (literally all service items replaced), but seems to suffer from a loss in top end power. It is really sluggish accelerating from 80mph and beyond (on a private road). The MIVEC is engaging at 5k rpm in all gears as it should, and the car pulls really well to the redline in all other gears. Whatever the problem is, the wind resistance and lower power of 5th seem to be highlighting this power issue.
The car will be going on a rolling road, but not until the spring, in the meantime I figure it's worth trying to diagnose the issue if possible.
The car is JDM, but it's definitely not the limiter kicking in (speed too low). RPM at certain gears has been cross referenced with another car, so it's got the correct gearbox. Front caliper had been binding, but this has been fixed and doesn't seem to be a contributing factor. all other calipers seem fine.
it's due to have the valve clearances adjusted as these need doing, but i wouldn't expect that to cause such a drop in performance.
My initial thoughts are fuel system issue, or something being blocked in the exhaust somewhere. Any thoughts?
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