Engine studders..., any suggestions? Options

[Benevolence]

Just recently I noticed when I slow down in 2nd, 3rd,4th, or 5th gear inbetween 1k-2k rpm that my engine studders (as in shakes back and forth) until I get past 2k rpm, or if I mash the gas pedal between those rpm I noticed my engined goes really slow until it gets past about 2100k rpm and it launches fast (feels like a mini turbo). It never did this before and is getting on my nerves because I have to go over a lot of speed bumps when I go to class and I dont want to go to first gear everytime I am driving around 15mph. So if you have any idea's why this is happening please post. (also it started around when I put some 91 octane gas in my car by mistake, I dont think this matters since I used all that gas and refilled it with 87 and its still doing it.)

[remjay]

QUOTE (Benevolence @ Jan 28, 2003 - 7:01 PM)

QUOTE (remjay @ Jan 28, 2003 - 6:33 PM) QUOTE (west_minist @ Jan 28, 2003 - 6:29 PM) Try resetting the ECU by disconecting the battery for 5 mins. This could be injectors need cleaning, a bad oxygen sensor, bad spark plugs. ...even bad gas; happened to my moms car...rough idle, funny acting--next tank...smooth. Dont go to econo gas stations. Yeah I thought it was the gas too but I went through a tank of 91 octane at chevron, then after that I went back to 87 octane with exxon which both are two pretty good gasoline places (I get 90% of my gas from exxon) and I do avoid the "econo gas stations", but still it jerks.

Ok, just tossing the idea into the air. What I meant was this new tank of 87 could be the bad gas.

Also, as a sidenote, try not to let your engine go into the lower 1-2k rpm range when in 4th and 5th gears. Its lugging the engine and could lead to ping/predetonation.

If you get a chance, find a safe road and let the car rev. Stay in gear [try 2,3, and depending on space 4] till a little under redline. Do this for at least 5-10 min continous. This helps free any carbon buildup that could be causing some problems.