auto-max: 1st to 2nd gear (thud) shift

hey guys,

so i recently had 2 fuel injectors go - 1 was bad, other was cuz of no ECU signal (car computer) to it ...i replaced injectors AND i just changed the ECU ..and engine rides smoother BUT now (immediately after changing ECU):

-- engine light came on. codes pointing to EVAP Cannister purge valve or something ..will check on that soon - but its emission related i think

-- (the car is auto not manual) when car goes from 1st to 2nd gear - it shifts REALLY hard ..like a thud and whiplash style ..2nd -to 3rd and so on is ok though..

my questions:

-- is this EVAP purge code mean anything 'serious' - i'd rather focus on solving gear-shift issue

-- how could changing the ECU / ECM affect my car shifting 1st to 2nd gear?

-- What can I check further to see why the hard gear-shift?

As always - thanks for the replies.

sursh79




:iceslolan

I have hard shifting on my 95 too... also from 1st to 2nd and, like yours, 2nd to 3rd is fine.

Did u figure out the problem?

Thanks.

i'm not a tranny expert but.....look into the valve body....i know that this might cause the hard shifting.....i know that auto guys put the vb mod in the car to make the car shift harder and faster.....

The "thud" that you experience is the burned solenoid in your tranny. Have that replaced. I've had my solenoid burn out twice on me. I have '00 GP so maybe it's the same problem with your car. Hope this helps! :smile:

the evap problem could be something as easy as your gas cap is on too loose. i had a code pulled at autozone cuz of a service engine light and the guy said my vacuum lines were clogged. i tightened the cap and had the guy reset the code and it never came back. i've heard the purge valve on the evap canister won't open unless there is good backpressure in the fuel lines. this is just speculation, i don't know for sure.