Gradual power loss

[Roger Slater]

My 1986 Comanche 2.5 is gradually losing power, no where near the performance when it was new.  It now is very sluggish to the point that 5th gear is rarely usable Engine still sounds perfect, no oil burning and excellent oil pressure.   Catalytic was removed when new.  Air cleaner is new.   Total miles now 110,000.  Is this normal Behaviour or is there a specific known cause, valve springs perhaps??

Thanks

Roger

[89 MJ]

I'd start with a compression test.

Has the rear axle ratio been changed?

How does it run when it is cold compared to when it is up to temperature?

[Roger Slater]

Compression test, good idea.

Axle ratios are original.

Starts and runs smoothly, hot of cold. Idles at 750 RPM.   It simply could not pull the skin off a race pudding.

Thanks for suggestion.

[hgeranium]

Fuel pressure is ok?

[pizzaman09]

What's the spark plug condition?