hi i have a 1997 eclipse gst auto and when i first start the car and put it into drive from park it hasitates to go into gear for less than a second and like bucks into gear not to hard. Also when i drive it, it somtimes shifts hard if i am not consistant on the amount of gas im giving it. Like if im accelerating fast then i let off it shifts down hard. I just has a full tranny flush done and got a new gasket and filter. I thought it was an engine mount but there is no shaking or strange noises at all when ever i drive the car. Its just the shifting. And sometimes when i slow down to about 15-20 mph it shifts down and bucks forward and help me slow down lol. I wonder if i just need to get a tune up? Ive herd this is sometimes normal with eclipse's though. I just had to replace my MPD sensor and i left the battery cable unplugged after for about a half hour. Maby the engine will reconfig everything itself the right way and the problem will go away??? Do you thing the problem is that i need a tune up? Dont get me wrong sometimes when im driving the tranny shifts fine like its brand new......O and the car is unfortunatlly stock right now......any help is greatly appreciated!

Well, I might not be able to be much help BUT...Almost the same thing happens to my car (98 Eclipse RS). Only, the problem is slightly different. When I shift from park to drive or reverse, the car jerks really hard. Then when I try to drive it stays in second gear the entire time...won't shift up or down even if I put in in L or 2. I've read that the car is putting itself in a 'safe' mode and it will do this to keep from breaking other stuff but the check engine light never comes on and I never have any other problems.

Anyway...all I do is turn the car off, disconnect the positive battery cable for like 30 seconds and then reconnect it and everything goes back to normal. I've only ever had to do that like three times though.

Do you ever hear any electronic sounding clicking noises coming from your tranny when you move from park to gear, or when your trans shifts (up or down). Mine does that and I was just wondering what it was. lol

it's the torque converter

garrett check your transmission and motor mounts

luckily my car makes no noises of any kind. The only noise it makes it when the belts get dry and all they need is a little silicone spray and there mint. And i just put some trans-x or whatever in my tranny to protect it from the hard shifting. Sometimes when i put it into drive it shifts fine and last light i was driving i tried to get going to get around a car and all of a sudden the car rpm's went up and the car wouldent go any faster..... I let off the gas and the car then shifted into the next gear wtf!! I think i need a tuneup now real baaaaad..... I think i screwed myseft by clearing that ecu and eracing the setting that the car had set by disconnecting the negative battery cable....i think the car adjusts over time to carbon biuld up and wear and now its not set to accomodate to all of the wear on a ten year old engine. BUT AT LEAST THE CHECK ENGINE LIGHT DIDNT COME BACK ON LOL.....what do u think?

your ECU only controls the engine. the TCU controls the transmission. the additive you put in there is the cause of the new problem.

A little off topic, but I've heard TCU (transmission controll unit) and PCM (power controll module) used interchangibly. Are they the same thing? Back to the topic. I agree it must be the torque converter. And most of the time those addatives do more harm than good, I'd stay away from them If I were you.

HEY GARRET I HAD THE SAME PROBLEM LAST YEAR WHEN I CHANGED THE ENGINE ON MY CAR. THE MECHANIC BY SOME REASON DIDNT TELL ME THAT I NEEDED ENGINE AND TRANNY MOUNTS I THOUGHT IT WAS FUNNY UNTIL HE TRIED TO CHARGE ME 600 HUNDRED TO REPLACE THEM LOL. BUT TOOK IT TO ANOTHER MECHANIC AND 0NLY PAID 200 BUT THAT SOLVED EVERYTHING. JUST CHECK ALL THE MOUNTS SPECIALLY THE TRANNY.

the additive cant be the cause of the new problem because it was happening before i put the additive in. The stuff i put in was lucas oil and its been helping the hard shifting a bit!

lucas oil kills dsm's

did you check the mounts?