hey cant figure this one out lol. ive been having a rpm surge for quiet a bit of time. cars getting the worst gas mileage ive ever had. first thing is when idleing the car will run normal while warming up but once i sit and idle it surges like crazy sometime i have to press the brake a little harder at lights or ill move forward. another surge problem i am having is ill be driving and let off the gas. after a few seconds the idle will go from 1000 rpms to 1500/2000 and then come back down and go right back up again. not sure where too start. replaced the coils and plugs about a year ago, cleaned throttle body and maf sensor. any ideas????

 

Idle air control valve?

 

Did you clean the MAF sensor to try and fix the problem? Or did you get the problem after cleaning the MAF sensor? You have any codes present? If I were to take a guess, I would say Idle air control valve like the previous guy mentioned. I would also consider looking at the throttle position sensor, I had one go bad in a mustang and it caused the entire car to surge. IAC valve when plugged up or bad usually just causes an erratic idle. Also check for vacuum leaks.

 

its your idle air control mine is doing it to but its not cheap to change might try and pull it off and clean it with some maf cleaner the IAC is located on the bottom of the thottle body

 

finally found sometime too check it out again. i replaced iac sensor and cleaned the inside of the throttle body and the valves for the iac. ive finally got the car to idle at 900-1000 rpms but this did not solve the surgeing idle while coasting in drive. i did notice it only surges when rpms hit 1000. it"ll bounce from a 1000 to 1500 no matter what gear or speed. asked my mechanic what could possible be going on and he wasnt sure due to the fact of cleaning everything and replacing the iac sensor. anymore ideas out there???

 

throttle position sensor and make sure cable to throttle body is working properly