My 1996 Mitsubishi Eclipse 2.0 Non turbo runs great 25% of the time. Other 75% of time rough idle, spits sputters, chugs at take off and idle. Car acts like it has a rev limiter on it at 3500rpms (stutters). Changed: fuel pump, fuel filter, throttle pos. sensor, temp sensor, coils, plugs, wires, and other sensors. Check engine light giving me the run around. Driving me crazy, when it runs crappy. Driving me anywhere when it runs great. Sometimes car runs great for a couple of days. HELP!!!!!!!!!

You may have an old engine oil, why don't you have your car service and change oil and oil filter as well. Then if the problem still appears, then that's the time to start tracing where the problem really starts.

try changing the fuel filter and fuel pump. it may have trash in it.

i would go with your line of thought to be honest

Yes by disconneting the map sensor will drop idle and make run rough, the problem is the idle air control valve or a vacuum leak, try to clean the throtlebody with an old tooth brush and some throtlebody spray cleaner if that doesnt help then try having the iac valve checked the iac valve (Idle air control valve ) if with the engine running listen for a hissing noise that will be a vacuum leak, these are the most common reasons for higher than normal idle. hope this is helpful.

i have a 97 eclipse and when my gas light comes on i have 10 to 20 miles until i run outa gas. depending on how you car runs and if it is turbo or not. on a non turbo 420a motor w/ a 5 speed i can do this.

mine sputters under 4000rpm

The rattling can be the exaust pipes hitting the car as the engine shakes. A vacume leak is a possible problem as the car has been worked on alot as the turbo is gone and the system was made to have one I hope you did'nt give much for this problem child as they go wackey and stay that way pretty easy. The check engine light is most likly on when running or it doesn'tr work one. Engine control codes need pulled and if mixture controll cdes are in the list the map senser hose needs checked the timing both ingtion and cam . The control codes could tip you off that the map senser isn't getting vacume and maybe applying an outside vacume sorce to the senser can clue you in to the other problems. ( make the computer think there is good vacume so it'll run smoth enough for you to find the leaks ) Ordinary compression cheak may find low cylinders as burnt valve and wore out engine are posible. These cars when HOTRODED can't last long and the tuner boys pull their money out after they blow em and sell the car as it's done as far as money goes.

Do a cooling system pressure check for a blown head gasket.

ok heres the thing when a car sets for a long time you have to do more then just clean the tank you also need to flush and replace all fluids in it and replace the fuel filter (that one is key because it empties out the fuel lines and injectors) and also please do youself a favor and replace the timing belt i can not stress that enough every 60,000 miles or 18 months please just to be safe replace the timing belt these 6 bolt 2.0 engines are great and so easy and cheap to build but if you brealk that timing belt you will be buying a new engine but truth be told sonds like you have and intake sensor thats gone out pop ur air can off and check the mas for a wasp nest or something like that