92 performance problem

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Mar 5, 2017 | 10:13 AM

flyingmonk

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5th Gear

Joined: Mar 2017

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92 performance problem

I have a 92 LT1 That Jerks when I punch the gas. It had been sitting in the garage for 2 years because it needed a new Optispark. Idles great and runs fine otherwise.

Things that have been done:
. Optispark
. Spark plug wires
. fuel pump
. fuel filter
. fuel pressure is fine at idle and under load
. Ohms on injectors are within range
. cleaned throttle body

I'm starting to lean towards O2 sensors or maybe the cats?

Last edited by flyingmonk; Mar 5, 2017 at 10:14 AM.

Mar 5, 2017 | 10:17 AM

antfarmer2

Race Director

Joined: Mar 2015

Posts: 15,926

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O2s and pull your knocks while your under there for a proper flush.

Welcome to the forum.

Last edited by antfarmer2; Mar 5, 2017 at 10:20 AM.

Mar 5, 2017 | 10:24 AM

flyingmonk

Thread Starter

5th Gear

Joined: Mar 2017

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Thanks for the quick reply. I pulled the knock sensors and flushed it when I replaced the optispark. I'll go ahead and replace the O2s and report back what happens.

Mar 5, 2017 | 07:16 PM

FAUEE

Race Director

Joined: Oct 2012

Posts: 17,339

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From: Melbourne, FL

Did you get the plugs/wires in the right order? Having the firing order wrong can cause it to feel like that.

Mar 5, 2017 | 10:16 PM

aklim

Team Owner

Joined: Jul 2004

Posts: 28,432

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From: Hartford WI

Quote:

Originally Posted by flyingmonk

. fuel pressure is fine at idle and under load

. Ohms on injectors are within range

. cleaned throttle body

I'm starting to lean towards O2 sensors or maybe the cats?

Does it catch up when you WOT it quickly?

That is a "Dr Feelgood" test. Makes you feel good but does nothing to identify if the injectors are crudded up or partially crudded. Having sat for 2 years, I'd bet there will be some flow improvement if you have it cleaned and tested. Mine show improvement and I have never let it sit for more than a couple of weeks.

Did you take the top plate off, IAC, IAC housing and clean the passages? New gaskets? Did the IAC counts show that you are having air leaks anywhere? Scanner should show about 30 counts, give or take with everything but the motor off and engine at full operating temp. If it cannot, turn the screw out, rev and re-read. If you are all the way out and still cannot achieve the counts and getting 0, you have an air leak.