Hello and good morning everyone!

I've got a million dollar question for all you people smarter than me(which is everyone). My car does something weird. Whats wrong?

Car: 2001 Mitsubishi Eclipse RS Hatchback, 2L, 4cy, Manual Trans, 95,550 miles.

Issue: When I start my car - hot or cold, AM or PM - it idles at about 600rpm. Very low. Its bogged down and sound/feels like its going to die, but it doesn't. If I let it run about 10 minutes in idle. it corrects itself.

If I drive the car before the 10 minute warm up, it feels like I'm starting in 3rd gear with no power, lots of hesitation and jerking. Once the car gets up to 3500RPM the car feels like it was down shifted into first and gets a boost of power! The wheels break free and I 'skirt' a little bit. and its very consistant. <3500 chug, chug, chug. >3500rpm VROOOM!!

When street driving(once I get going), its the same, at any speed, any gear under 3500rpm its jerking, bogged down, hesitant, Feels like its going to die. once I get to 3500rpm+ it gets a swift kick in the *** and drives VERY good.

I consistantly have the 'check engine' light on (P0133 O2 Sensor Circuit Slow Response (Bank no. 1 Sensor no. 1), the existing O2 sensor was about 3 months old. I bought and installed a new one. and get the same code. I'm convinced its not the o2 sensor, its just a false reading. Also my MPG has taken a poo, a SERIOUS one at that. I'd figure less than 10mpg at this point.

I'm lost, please help. I have all the tools necessary to check OBD and circuts and Ohms, and god knows what else. Any advice would be great!

One last thing, This started about a month ago, and the only thing that changed was I added 1qt of oil. I don't see how its related as I've added oil to this thing off and on for 10 years now.

thank you in advance!

 

iac motor is bad

 

Ok, its been 2 months now. I've replaced the;

Idle air controller
Throttle position sensor
spark plugs
air filter
throttle body

The car still runs like sh**!!!

....... I'm about to call the stealership and take the $150/hr diagnostic. I'd rather not do that....

Anyone else want to chime in on this and take a stab at what might be wrong?

if you need more information, please let me know, I will be checking this site multiple times a day.

Thank you to everyone in advance

-me