Corvette 1992 LT1 - misfire

[Quasar C4]

My C4 badly misfired and then backfired when flooring it a couple of days ago. It happened at about 3500-4000rpm. Having backed off the throttle it recovered itself after a few seconds and then ran fine below 3000rpm. It did the same again today. Runs fine below 3000rpm.

Checked the relevant work done on the car.
New Optispark distributor and ignition control module in Nov 2018 (42,240 miles)
Injectors cleaned, new plugs & HT leads and fuel filter fitted by me in Mar 2022 (43,212 miles) just after buying the car when it was only running on 6 cylinders.
Has run fine since. The car’s only done 50,000 miles and is in great condition.

Has anybody had a similar experience.

 

[Oneball]

When Ive had similar symptoms (not in a C4) it’s usually rotor arm, dissy cap or ignition module. I’d try changing the rotor arm. Relatively cheap and easy to do.

 

[teamzr1]

Check fuel rail pressure, using the test port, should be around 43 PSI at idle
when was the last time the fuel filter was replaced ?

Are those the original fuel injectors ?
When was last time they had a good cleaning with an injector cleaning machine or maybe degraded due to age and also Ethanol in the gas they were not designed for and are carbon'ed up
Check the O-rings at both ends of injectors as leaking and pulling in air

Check for exhaust leaks like at the exhaust manifolds and check sparkplug tips and gaps

Unit I have cleans and tests injector for proper flow and not leaking



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