What causes rough idle and surging after warm up?

Rough idle and surging after… Rough idle and surging after warm up on my 90 L98 Corvette (33k) no codes showing. Parts replaced; fuel filter, plugs, wires, distributer cap, rotor, EGR valve, oxygen sensor, injectors cleaned, throttle body cleaned, dry gas used in tank.

What can I do about a rough engine idle?

You can clean the (MAF) sensor yourself, with an aerosol can of (MAF) sensor cleaner. Sometimes dirty fuel injectors, can be the root cause, of a rough engine idle. Fuel injectors disperse fuel into your vehicle’s engine; at a precise angle and quantity, to ensure optimal performance.

Can a bad fuel pressure regulator cause a rough idle?

Once warm, a bad fuel pressure regulator can cause a rough idle by leaning out the mixture due to low fuel pressure. A Fuel filter would not cause a rough idle when warm. A clogged fuel filter would cause far more problems on a cold start when fuel demand is higher.

What causes a car to idle when it’s warm?

Once warm, a bad fuel pressure regulator can cause a rough idle by leaning out the mixture due to low fuel pressure. A Fuel filter would not cause a rough idle when warm.

When does a car have a rough idle?

November 27, 2017. It’s easy to tell when your car has a rough idle: When you start the engine, it won’t run at a steady rate. It may almost stall, or it may run at varying RPMs without your putting your foot on the gas, or it may do both.

Is it hard to start a 1988 L98 auto?

1988 L98 Auto. recently aquired. hard to start from cold start. literally 3-7 seconds on the starter. New wires, not plugs. new cap and rotor. trust me being a Jeep guy I know oil smoke smell. Once she is running, she starts slow then idles fine. after that no performance issues.

Why does my 90 L98 Corvette have black smoke?

A lean exhaust, with an oxygen sensor output fixed above 800 mV (0.8 volt), will be a contaminated sensor, usually silicone. This may also set Code 45. System rich (Low Air/Fuel Ratio) – Idle speed too low. “Scan” counts usually above 80. System obviously rich and may exhibit black smoke exhaust.