1999 Subaru Impreza throttle Flat spot

DJANABEL

MEMBER
1999 SUBARU IMPREZA

Engine Performance problem
1999 Subaru Impreza 4 cyl All Wheel Drive Manual 100k miles

ever since I bought my 99 RX impreza it has had a flat spot between 3000-4000rpm it loses about 50% of it's power and feels like, although accelerating, I have run out of fuel. The engine note flattens and the all the power goes away, once 4000+ rpm hits it goes back to 100% power. I have had Subaru mechanics look at it and even download the engine details and nothing appears.
It doesn't happen all the time. It will be there for a couple of weeks and then I will have no problems at all for a few days.
thanks

2 Replies

RASMATAZ

MECHANIC
75,992 POSTS

Have the throttle position sensor and fuel pressure checked

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Thursday, May 29th, 2008 AT 5:15 AM

MMARCAN

MEMBER
1 POST

Hi, I had the same problem with my 1999 subaru and I might have the solution for you. I had this problem since 1 year and it had drive me crazy. It's on and off. The car runs fine for a couple of days then it's start going bad again. You probably have a problem with your throttle. After many years there is a creation of dirt around the throttle that make it have problems positioning at low RPM. When you start accelerating the throttle will open slowly and let air go in the engine. If the throttle is dirty then it will sometimes have a position were it will stick an create a flat spot. At this point if you press harder on your accelerator your car will kick down and it will accelerate. Its normal because at that point you will get the throttle to open to its maximum and it will stop sticking in the dirt. The way to fixe that is to get your throttle cleaned. The last time I have seen this problem on a subaru the mechanic had to clean it with a tooth brush. That had solve the problem. Before you put any more money on your car, try this solution. Good luck and please answer me if it works.