Rough idle at a cold startup and sounds like it is misfiring?

ELSKI

MEMBER
1995 HONDA ACCORD
4 CYL
2WD
AUTOMATIC
150,000 MILES

The vehicle listed above is a wagon. It has a very rough idle at a cold startup and sounds like it is misfiring badly. After a brief minute or two it smooths out and seems good the rest of the day, the check engine light was coming on only while in warmup, but now stays on.
I found and jumpered the blue connector to get the codes which according to what I read should show up as flashes on the ck engine and ABS light light, which were 9 and 12 respectively. But also, the D4 light was flashing 8, and SRS was flashing 52, I must have been on the wrong code chart because none of them sounded like it might be causing the rough startup.

Help!

1 Reply

KEN L

MASTER CERTIFIED MECHANIC
42,896 POSTS

I would start with a full tune up, here is a guide to help:

https://www.2carpros.com/articles/how-to-tune-up-a-car-engine

Here are other possibilities for the problem:

Ignition system: The rough idle and misfiring could be caused by issues within the ignition system. Check the spark plugs, ignition coils, and ignition wires for wear, damage, or improper functioning. Replace any components that appear faulty.

Fuel system: A problem with the fuel system could also cause rough startup and misfiring. Check the fuel injectors for clogs or malfunctioning. Inspect the fuel filter for blockage. Consider performing a fuel system cleaning or using fuel additives to remove deposits.

Air intake system: Make sure the air intake system is clean and free from any obstructions. Inspect the air filter and clean or replace it if necessary. Check for any leaks or loose connections in the air intake system that could disrupt the air-fuel mixture.

Engine coolant temperature sensor: A faulty engine coolant temperature sensor can lead to incorrect fuel mixture during cold startup, resulting in a rough idle. Consider testing or replacing the coolant temperature sensor.

Idle air control valve (IACV): The IACV is responsible for controlling the engine idle speed. If it's malfunctioning or dirty, it could cause rough idle during startup. Clean or replace the IACV if needed.

Vacuum leaks: Examine all vacuum lines for leaks, cracks, or loose connections. Vacuum leaks can disrupt the air-fuel mixture and cause rough running conditions. Repair or replace any damaged vacuum lines.

Please go over this guide and get back to us.