CarAteMyMoney

Anyone know what might cause a power loss over 3000 rpms? Also it seems hesitant to rev in that area

but the thing still leaves 20 foot pairs of tracks from hitting the gas at a stop sign

nikh23

yea, the stock tpi system on a 350 can cause power loss over 3k RPM. Your best bet would be to switch over to a different induction system like the Holley Stealth Ram. If you don't have the money for that kind of setup you could always port out your stock plenum runners and base (depending on the fact that you actually do have tpi). Post a little more info about your car so we can help diagnose the problem.

CarAteMyMoney

what i meant by power loss was that this car feels much less powerful than any of my other L98 TPI cars

nikh23

when was the last time you did a tuneup?

CarAteMyMoney

when i got the car, in november. new cap, rotor, wires, 02 sensor...

i noticed on the scanner that my 02 voltage jumps from .3 to.8 back and forth and doesnt usually come close to .45 volts if that helps

im thinking maybe timing, leaky injector or bad ignition module could be the culprit but im looking for suggestions

nikh23

did you change the ignition coil? I don't know if that'd be teh sole culprit but it def can't hurt

CarAteMyMoney

yup swapped in the coil from my other car, no change

nikh23

check your fuel pressure

CarAteMyMoney

hmm, good idea! what should it be? like 42 at idle right?

what about under load? is there any way to check it other than on a dyno?

Spdfrk1990

maybe that coil is bad my car use to do that until i changed my coil

nikh23

I think thats correct for the L98 motor, not entirely sure but its definitely in that range. dyno is the only real way to check it at WOT, or you could bring it to a track and try to test/tune it that way. While you're at it pick up an adjustable one, might as well right?

RSCamaroGuy92

I don't know if you went into this, but....
Have you checked your fuel filter lately??? I had a similar problem with my '92, the fuel filter was dirty and it wouldn't allow enough fuel to enter the injectors. I didn't notice if you mentioned checking it, sorry if you did.

Either way, sounds to me like your "leaning out" the motor. I'ld go after the fuel delivery system, then check out ignition.
Just a thought, keep us informed

bjankuski

Check for a clogged cat. Low will still be good but top end will suffer.

CarAteMyMoney

i'll do the fuel filter tomorrow.

i have one cat per side - how should I go about checking them?

nikh23

would a bad cat really cause that much power loss? I guess you could check to see if the outside of the cat is all burned and charred looking, thats a good indication that cat is done. Also if your exhaust smells like rotten eggs. Best way is to jam a pipe through them and reattach them back up to your exhaust and call it done hehe.

Spdfrk1990

i had a cat go bad on a 4 cylinder car b4 and it hardly had ne power till it got fixed

bjankuski

A bad cat will kill all upper RPM power if it is clogged. I had a 350 GTA that had a bad cat and it would launch ok but then quickly run out of breath. With the bad cat it ran the quarter in 15.97 at 85 MPH. Once I replaced the cat it ran 15.15 at 92 MPH and reved nicely to 5000 RPM.

CarAteMyMoney

fuel filter helped a little, but not much.. it's still not how it should be

within the next 2 weeks ill be doing the ignition module, injectors, timing, and whatever other little crap i can think of

i noticed that the return line near the fuel filter is pinched, but not too bad, would that have anything to do with it?

nikh23

that can definitely be the problem. i'd get that fixed before anythign else.

RSCamaroGuy92

Quite simply, I think that MAY be your only problem, I'ld still say get an adjustible fuel pressure regulator and a guage, I say that your problem is Fuel related.

CarAteMyMoney

wouldn't a pinched return line hurt off-idle power more than high rpm? since more fuel would pump into the engine

wait a sec... how could a pinched return line hurt the performance, anyway? isnt it all regulated?