kaotik

iTrader: (1)

I have a 91 Camaro with a 99 vortech 350 bottom end and original 305 TPI top end.

Car runs fine if I feather it up to speed. If driving down a street with buildings on both sides, you can hear what sounds like a turbo spooling or air passing.

At a dead stop if I punch it WOT it falls flat on its face and there is no power at all.

Anyone have an idea of what this could be? I don't want to nickel and dime it to death to figure it out.

My guesses are clogged cat converter, (but no smell currently), TPS sensor, intake manifold leak, Timing issue.

Thanks for any feedback if you've seen this before, or have any ideas.

ex-x-fire

Low fuel pressure, these tbi engines will run on very low fuel pressure (like 4-5psi), just not very well. Stock spec is 9-13 psi. Rent a "tbi" pressure tester at Auto Zone.

Rockyd

When u swapped over to to 350 did u swap the knock sensor and the electronic spark control for 350 specified?

kaotik

iTrader: (1)

I will give this a try... could be.

kaotik

iTrader: (1)

I didn't do the swap, but both good questions.

Only response I have for now, is that it has run very well the last 6 years and this issue came out of no where, so I assume that isn't it.

kaotik

iTrader: (1)

So after letting it run for awhile idling and going over the car listening I determined it is a plugged Cat. I heard a knocking noise that almost sounded like it was coming from the bottom end of the engine, but later found it to be something rattling around in the Cat itself. This would explain the noise and loss of power. Its also running super rich right now too...

I will be fixing it sometime this week and expect that to correct the problem. I will report back for sure.

Thanks all for thoughts and help!

kaotik

iTrader: (1)

So I replaced the Cat with a test pipe and that was it. Runs like a top now! sounds a little deeper and really pulls. There was a HUGE chunk plugging the outlet.