Poor performance[97Civic DX, manual trans]

Hi,
I bought a 97 civic dx (118K miles old) recently and I noticed cars with supposedly lesser hp (sentra, protege,...) accelerating faster than mine from a signal. I had an oil change, had the spark plugs changed. The mechanic said the air filter is fine. There is no check engine light on. I check the pressure in the tires regularly. The acceleration from the stop or while going uphill is the only problem I have (the car actually starts decelerating from 40mph in the 4th gear on even slight slopes)
Can someone tell me what should I tell a mechanic to have him check for any related problems. When I asked goodyear, pepboys and other mechanics around, they all mentioned 350 for a complete checkup. But I dont want to spend so much, at least not this year. Can it be a clogged fuel filter even if the car runs fine at 70mph? I don't know if the previous owner changed the coolant or transmission fluid at 105K miles as the owners manual says. Can these affect acceleration?

Thanks

Your clutch might be slipping. While going up hills, does your engine accelerate but not your car?

Nope. If I let it stay in the 4th gear, the engine also starts slowing down.

Hi,
I bought a 97 civic dx (118K miles old) recently and I noticed cars with supposedly lesser hp (sentra, protege,...) accelerating faster than mine from a signal. I had an oil change, had the spark plugs changed. The mechanic said the air filter is fine. There is no check engine light on. I check the pressure in the tires regularly. The acceleration from the stop or while going uphill is the only problem I have (the car actually starts decelerating from 40mph in the 4th gear on even slight slopes)
Can someone tell me what should I tell a mechanic to have him check for any related problems. When I asked goodyear, pepboys and other mechanics around, they all mentioned 350 for a complete checkup. But I dont want to spend so much, at least not this year. Can it be a clogged fuel filter even if the car runs fine at 70mph? I don't know if the previous owner changed the coolant or transmission fluid at 105K miles as the owners manual says. Can these affect acceleration?

Thanks

well you might need a new fuel filter along w/ an injector cleaning possibly...

Can you also tell me if a mechanic can tell if the coolant & transmission fluid needs change. When I asked the mechanic last time, he just told me after the visual inspection that he is not very sure what the condition of these fluids is, but would reccommend I have them replaced (for $35+$35). Is he correct when he says there is no way to tell by visual inspection if these need to be changed?

well you might need a new fuel filter along w/ an injector cleaning possibly...

well if the coolant has no color or a brownish color then I would say it's bad...as for the tranny fluid you would have to drain some and see if it looked redish or dark and grungy...
if you are unsure if either have ever been done then go pick up the fluids and take care of it. Also purchase a Helms manual if you don;t have oen as it's a great investment.. Good luck.

check your timing. if the timing is off you can lose a ton of power and you might not notice untill you go up hills or higher speeds.(this happend to my bother after hes motor was changed and no one botherd changing the timing)

Does it sound like your engine is choking, or not giving the right sound or anything when it starts acting up? If it is akward sounding and it starts decelerating while your trying to accelerate i would try checking the catalytic converter. My Chevy 89 C1500's cat was clogged and it ran really boggy from a start, but once it got to third gear or past 35 mph it would seem normal, except for the 55-65 mph range, then it would get boggy and decelerate unless i floored it for a bit. If its anything erratic like that or sounds a little goofy or choking like i would definetally check the cat out.