# 2003 Mitsubishi Eclipse RS loses acceleration power at 4000 RPM **URL:** \ **Category:** Maintenance/Repairs\ **Tags:** acceleration, rpm, clutches, eclipse, mitsubishi\ **Created:** [May 28, 2009, 9:41pm UTC](https://community.cartalk.com/t/2003-mitsubishi-eclipse-rs-loses-acceleration-power-at-4000-rpm/31112 "2009-05-28T21:41:19Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![lucasm822](https://avatars.discourse-cdn.com/v4/letter/l/b5e925/32.png) [@lucasm822](https://community.cartalk.com/u/lucasm822)\ **Post date:** [May 28, 2009, 9:41pm UTC](https://community.cartalk.com/t/2003-mitsubishi-eclipse-rs-loses-acceleration-power-at-4000-rpm/31112/1 "2009-05-28T21:41:19Z")
After replacing my clutch, bleeding air from the radiator hose, and bleeding the slave cylinder, I now have a problem that seems completely unrelated, but started only after these fixes. When I run it around 400 RPMs in any gear, the acceleration almost halts, regardless of terrain, climate, etc. What should I be looking for? There are no warning lights, the clutch does not slip, and all the fluids, filters, etc. have been changed. ---
**Author:** ![lucasm822](https://avatars.discourse-cdn.com/v4/letter/l/b5e925/32.png) [@lucasm822](https://community.cartalk.com/u/lucasm822)\ **Post date:** [May 29, 2009, 1:36am UTC](https://community.cartalk.com/t/2003-mitsubishi-eclipse-rs-loses-acceleration-power-at-4000-rpm/31112/2 "2009-05-29T01:36:48Z")
Going for a bump up. It may seem trivial, but the lack of acceleration means something is not working correctly, and that truly irks me… Another question along with this- Are timing marks, the coil packs, or the air intake potentially the cause of this? ---
**Author:** ![lucasm822](https://avatars.discourse-cdn.com/v4/letter/l/b5e925/32.png) [@lucasm822](https://community.cartalk.com/u/lucasm822)\ **Post date:** [May 29, 2009, 3:17am UTC](https://community.cartalk.com/t/2003-mitsubishi-eclipse-rs-loses-acceleration-power-at-4000-rpm/31112/3 "2009-05-29T03:17:15Z")
I don’t know if there is a formal way of bumping posts to the top of the forum, so I’ll settle for posting on my own topic. Is there something in my post or question that is keeping people from responding, or is there not a problem that anyone can find? ---
**Author:** ![the\_same\_mountainbike](https://avatars.discourse-cdn.com/v4/letter/t/c89c15/32.png) [@the\_same\_mountainbike](https://community.cartalk.com/u/the_same_mountainbike)\ **Post date:** [May 29, 2009, 10:06pm UTC](https://community.cartalk.com/t/2003-mitsubishi-eclipse-rs-loses-acceleration-power-at-4000-rpm/31112/4 "2009-05-29T22:06:22Z")
The only thing keeping me personally from responding is that I don’t have an answer. Normally I’d suspect a breathing problem for acceleration pooping out at 4000 rpm, such as a restricted exhaust, but I cannot think of anything related to the work performed that might cause this. Sorry. I’m stumped for ideas. ---
**Author:** ![hellokit](https://avatars.discourse-cdn.com/v4/letter/h/6a8cbe/32.png) [@hellokit](https://community.cartalk.com/u/hellokit)\ **Post date:** [May 29, 2009, 10:44pm UTC](https://community.cartalk.com/t/2003-mitsubishi-eclipse-rs-loses-acceleration-power-at-4000-rpm/31112/5 "2009-05-29T22:44:20Z")
Some engine computers are designed to limit rpm to prevent damage to the engine. If yours has this feature, it could be faulty and reducing rpm too low. The crankshaft position sensor may be the sensor the engine computer depends on for this control. I’ll leave the research to you. Here is how to check the crankshaft position sensor. There are other instructions, also: [http://www.autozone.com/autozone/repairinfo/repairguide/repairGuideContent.jsp?chapterTitle=Components+%26amp%3B+Systems&partName=Engine+Performance+%26+Emission+Controls&pageId=0900c152801d6564&subChapterTitle=Crankshaft+Position+Sensor&partId=0900c152801d64e5](http://www.autozone.com/autozone/repairinfo/repairguide/repairGuideContent.jsp?chapterTitle=Components+%26amp%3B+Systems&partName=Engine+Performance+%26+Emission+Controls&pageId=0900c152801d6564&subChapterTitle=Crankshaft+Position+Sensor&partId=0900c152801d64e5) ---
**Author:** ![waterboy](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/waterboy/32/764_2.png) [@waterboy](https://community.cartalk.com/u/waterboy)\ **Post date:** [May 29, 2009, 10:53pm UTC](https://community.cartalk.com/t/2003-mitsubishi-eclipse-rs-loses-acceleration-power-at-4000-rpm/31112/6 "2009-05-29T22:53:59Z")
With any problem start with the basics and work your way up. Miles? latest air filter, fuel filter, plugs miles ago etc.? ---
**Author:** ![lucasm822](https://avatars.discourse-cdn.com/v4/letter/l/b5e925/32.png) [@lucasm822](https://community.cartalk.com/u/lucasm822)\ **Post date:** [May 29, 2009, 11:01pm UTC](https://community.cartalk.com/t/2003-mitsubishi-eclipse-rs-loses-acceleration-power-at-4000-rpm/31112/7 "2009-05-29T23:01:22Z")
161,000 miles, regularly maintained. New air filter and fluids. don’t know if the fuel filter has been replaced. as for the plugs, if you’re referring to the spark plugs, i don’t have a clue…