Lares733

Hello everyone.
Please, need help with my 90 vette 172k. Just drove Miami to Ft. Lauderdale, Fl about 44 miles. On my way back car started to run rough and upon acceleration and deceleration it backfires. Checked as much as I could. Filled up with premium gas, injector cleaner, no codes, recent plugs, wires, fuel pump, rotor, cap. Injectors about two years (5k ago). Just checked timing (6 btc). Idle about 600 rpm. Can't figure out. Possible bad injector? Any suggestions .
Thank you in advance.
Rick.

65Z01

First I'd check fuel pressure, with the hose disconnected and plugged.

Next I'd check compression to see if any problem with the valve train.

Lares733

After checking resistance to injectors, I discovered that # 5 injector, the resistance is 1.8 ohms. Will replace next week, also, great time to delete emissions and EGR valve to clean up engine bay.

DinoBob

Leave the emissions alone, please. We car guys get a bad enough rap without someone deleting equipment that works as designed and does not rob horsepower. Your kids breathe too.