Edmunds Answers

Voted Best Answer

  • avatar karjunkie 03/06/10 9:46 am PST

    Usually, this indicates a problem that existed in warm weather but got worse and more noticeable in cold weather. I assume that you mean you have a rough idle or a hard time keeping the engine running until it has warmed up. If so, the first step is routine maintenance items that don't cost much and should be done anyway. Change the spark plugs, spark plug wires, fuel filter and the air filter. A worn spark plug or clogged air or fuel filter will cause rough idle and cold start problems. Change the PCV valve and clean your EGR valve as it may also contribute to these problems. The PCV valve is very important, if it’s clogged your car will run rich wasting gas and making it run rough. It just pops out of the valve cover and is an easy fix. The EGR valve is connected to the intake manifold and can be removed and cleaned with throttle body spray cleaner. Make sure your injectors are clean and functioning properly. Run some Techron Concentrate injector cleaner through a couple of tanks of gasoline. Clean the MAF sensor wires in the intake plenum with CRC sensor spray as dirty sensor wires will cause your car to run rough at idle. Lastly, start running only tier one gasoline in your vehicle. I only use Chevron or Shell and have very few problems with the throttle body or injectors fouling. Good luck and let me know if you have any follow up questions!

Answers

  • karjunkie 03/06/10 9:46 am PST

    Usually, this indicates a problem that existed in warm weather but got worse and more noticeable in cold weather. I assume that you mean you have a rough idle or a hard time keeping the engine running until it has warmed up. If so, the first step is routine maintenance items that don't cost much and should be done anyway. Change the spark plugs, spark plug wires, fuel filter and the air filter. A worn spark plug or clogged air or fuel filter will cause rough idle and cold start problems. Change the PCV valve and clean your EGR valve as it may also contribute to these problems. The PCV valve is very important, if it’s clogged your car will run rich wasting gas and making it run rough. It just pops out of the valve cover and is an easy fix. The EGR valve is connected to the intake manifold and can be removed and cleaned with throttle body spray cleaner. Make sure your injectors are clean and functioning properly. Run some Techron Concentrate injector cleaner through a couple of tanks of gasoline. Clean the MAF sensor wires in the intake plenum with CRC sensor spray as dirty sensor wires will cause your car to run rough at idle. Lastly, start running only tier one gasoline in your vehicle. I only use Chevron or Shell and have very few problems with the throttle body or injectors fouling. Good luck and let me know if you have any follow up questions!

ADVERTISEMENT

Top Subaru Outback Experts View More

Rank Leader Points
1. MrShift@Edmunds 655
2. Stever@Edmunds 430
3. karjunkie 410
4. morin2 185
5. zaken1 140
6. canddmeyer 130
7. texases 105
ADVERTISEMENT