03 to 02 3400

[McNastie]

I have to put a motor in a 03 grand am gt the only thing i can find locally is out of a 02 Alero. The interchange said 03-05, realizing most of it will be the same what are the differences going to be? thank you.

[slowalero]

There weren't that many differences in the LA1 3400 found in N-body's (Grand Am, Alero), especially between those years. It is however technically illegal to swap an older engine in a car. This is purely political, and it refers to the fact that each year emissions standards are updated. As far as I know, emission standards didn't change those years. If they did, GM got away with tuning the PCM.

The biggest difference in 3400's came in 2000 when the injectors changed, the upper intake manifold changed for the new EGR valve, and camshaft position sensor changed. Obviously, your car is newer than 2000 so these changes don't apply to you.

There are some other, smaller differences but they too are impertinent details.

[bob442]

the spark plugs might* be different lol

[McNastie]

Swapped the motor out and runs great now its not shifting right. it will accelerate but you have to lift off the pedal slightly for it to shift and it wont go into passing gear, the car downshifts but then just revs up to about 3500 and doesnt accelerate. Thinking the valve body is sticking, or maybe I should try the spark plugs. lol

[bob442]

check your MAF and TPS sensor and check back, MAF will effect APC pressure and TPS will effect shift patterns

[McNastie]

will do, I thought about the TPS but not MAF. I will do that. thanks.