I have a 1999 Chevy Blazer 4.3 4x4 automatic. I recently put new intake gaskets on put it back together it runs good but now when you put it into gear you have to give a lot of gas to even move especially reverse checked all plugs to make sure they are plugged in tight fluid level is good no codes either any suggestions

Make sure all of your vac lines are connected.

Already checked that I figure it'* electrical somewhere it acts like it'* in gear and in park at the same time.

Did you check ignition timing?

Yes I did the engine runs great runs good when put in gear when you put it into gear it don't want to move have to give a lot of gas to get it move like something is holding it back not driving it so I don't burn the trans up have a friend with snap on scanner gonna hook it up today.

I'm thinking the same thing, timing is off.

Will timing being off make the transmission not shift or not pull

It gives the feeling of no power.

Put a vacuum gauge on it.

I'd guess the transmission is binding up if you hadn't just had the intake off.

What does the timing angle show at idle?