Engine Problem

[Leeroy]

HELP REQUIRED - I have a 93 4.2 EFI only purchased 5 mths ago - Engine seems to struggle for power when climbing hills (under load of course) - I am having to continuosly pump the accelerater to get any power to the wheels - Car has 322,000 k's on it but has been wee looked after - I have changed the fuel filter twice - the 1st time gave a good improvement initially but it did not take long for it to start playing up again - When the 2nd filter was replaced there was no change at all - Under normal driving conditions the car seems to run fine, bit of a lag changing gears is all (is an auto)
there are no leaks at all and the car never runs hot (except the time I filled the radiator with mud)
Any ideas on where I should start or what it might be?

[patch697]

How log has is been since its last full tune up ie. plugs, leads, injection service that sort of thing & the same for the auto trans?

[Leeroy]

Yeh not quite sure - What I know is that the engine had a major overhaul about 25,000 km's ago - But the bloke I bought it from serviced the car himself - He only ever used to drive his wheel chair bound daughter around in it so it has had a pretty easy run for atleast 3 years or so. What would plugs leads and an injector service cost me "ball park" of course

[patch697]

depend on where you go & what it needs????

Do you have duel fuel?