lossing accelleration when

Up hill it loses accelleration.

Hard to start when cold.

first any vehicle will lose speed when going uphill when either A you have cruise control on or B you keep the pedal at the same place however if you have acceleration problems when you floor it going uphill it may be time to change oil, airfilter, spark plugs, plug wires, and your remaining ignition system. i could provide a better response if i knew a little bit about your GMC like engine size and intake type(ex. TBI, DPI, carbuerated etc) the cold starts and acceleration are a combined problem and from what i can tell it is most likely a faulty ignition module. thats the problem i had with my suburban - replaced my ignition system with an MTI economy model and not only did i increase my mileage about 3 miles a gallon i got about 20 more horses and 40 FT/lbs of torque

Up hill it loses accelleration.

Hard to start when cold.
1992 GMC Jimmy 4.3 v6 vortec. Changed the fuel pressure regulator, was still hard to start, now will not start.

Can you stop being so cheap on the details.

How can you expect us to help with little to no information.

Can you stop being so cheap on the details.

How can you expect us to help with little to no information.

lol i realize i haven been here for almost a year but hopefully youve got e-mail notification turned on

from the sounds of it your fuel pump is out.
you can check that the safe way or the dangerous way

first the safe way, replace your fuel filter and prime it before you start it, turn the key to the on position without starting it. if you hear a noise that sounds like your cd-rom opening then your fuel pump is not out

dangerous way replace your fuel filter and keep one of the lines off turn the key on if gas sprays out its good. i cannot be held responsible for any injuries caused by option number two, but can be very effective for checking your fuel pump

Good susgestions about the fuel filter which is the cheapest way to start off first... My 2000 Jimmy was doing the same as you described but changing the filter didn't work for me .. Mine involved having the cadilic converter replaced .. I guess it was plugged up so replacing it gave me back the power to climb hills again ..........

Mine involved having the cadilic converter replaced Awesome point, i knew i was forgetting something :D