well when i bought my car 2 years ago it had just over 89K and ran great. i could slam the petal at a stop and it would squeal all the way down the road and roar through first and second gears of the automatic. but now at around 102K i just don't have the power i used to. if i slam the pedal at most i get a chirp if not nothing, and first gear takes an eternity to get through and second takes even longer at WOT. i can swear it accelerates faster at 3/4 trottle than WOT. that and i now have a very rough idle wether i run the engine cool with the cooling fan on or let it get up to 220 or so. the whole engine likes to shake at the 500-600 idle and you can feel it all the way up the steering wheel. i know its only a little puny 305tbi but i just put a $500 posi carrier in the rear and i only get to use it if i power brake or if its raining (maybe).

as far as maintenance its got new plugs, wires, rotor, cap, and coil. its also has a K&N lid and filter open element and a new fuel filter. i haven't been able to test fuel pressure yet but soon will. and how can i tell if my cat is clogged without ripping it off of the car (with massachusetts rust you have to rip it off). could my TBI unit need new injectors and a rebuild kit? i also though it might be that i'm losing compression slowly but i burn absolutely no oil at all and the coolant stays where it needs to. so what i'm asking is what else can i check other than the cat and fuel pressure? any help is really appreciated.

p.s.- i have access to a lift during my lunch break and an hour or two after work since i work at a dealership. too bad the only specialty tools i have access to are for hondas, mitsus, and nissans

 

my dad also has a 305 vortec in his 97 sierra and his is acting the same way, a loss in power ESPECIALLY in the lower rpm range.

 

you can't go wrong with replacing the cat for a high flowing one.

take off your air cleaner, start the car and look at the injector spray pattern, injectors could be dirty.

 

Vic_V8 has a good point about dirty injectors. Another couple things to check are:
1. Motor and transmission mounts.
2. Make sure none of the plug wires have been burnt through by the exhaust.
3. P.C.V. valve to make sure it's operating properly.
4. T.P.S. for proper adjustment.
5. Check the timing.
6. Make sure the Distributor is bolted down and not worn out or moving around.
7. Make sure your coil isn't faulty.
8. If none of this helps, perhaps a compression check might be in order.

Also, are you throwing any codes like an E.G.R. or O2 sensor.
Hope this helps you track it down.

 

no codes plus both egr and o2 are brand new delco parts, and i have 2 pcv valves (one on each valve cover) that are new from when i put on crome valve covers and the oil cap is also a breather cap as well. i'm also thinking it could be my manifold gaskets cuz when i drive by buildings i hear a loud noise from like the fenders. thankx for the ideas, i'm not sure if my work has a scope but if not i may be able to get my hands on a genesis or brick scanner.