1990 ZR-1 Hesitation when full Power

[tnova]

Mike, Long time since we last talked. Yup, surprised about finding the catalyst collapsed. After all the troubleshooting we did and not getting the stumble/lag resolved, especially when real-time testing with your Tech. I only stumbled on it when shelving the old exhaust manifolds and hearing the rattling around in the cat. Looking back, it was a classic symptom of blocked exhaust.


Recently had a cousin with the same symptoms on his daily driver and he found the catalyst collapsed in the converter. Replaced it and now runs like it should.


In chasing the symptoms you and/or I validated the operation of the secondary vacuum system, the FI drivers, replaced the injectors with FIC injectors, replaced coils, replaced O2 sensors, upgraded the fuel pumps, validated the secondary and FI signals from the ECM, and the prom. Not all for not but a lot of time and money.


Again, thanks for all the help.
Tony - Tnova