i finished putting the 98 motor in my car yesterday and put oil, coolant and everything. i bought a new battery and started it up today. it started up but was a little noisy for a while like clacky sounding, im sure it was the new oil getting to the lifters because the motor sat without oil in it for a while. the sound went away though, now my other problems are it runs really funny. not very good throttle response and it barely idols. im still tryin to get a scanner to see what codes its throwing at me.

i hope this guy didnt rip me off

 

Part of it is that the ECU needs time to learn what it's doing and self-calibrate. As it does, things will smooth out . It can take a few days. It may also help to get good contact cleaner like ProGold at an electronics shop and clean all the sensor and harness contacts. Put new vacuum lines in and when it starts to smooth out do a full seafoam treatment on it. Top off the tank now with high octane gas too - if your car sat awhile the gas may be breaking down some. Pour a can is seafoam in and fill on top of it with high octane. All of that will help. Scanning is a good idea even if you don't have a CEL. AutoZone does it at no charge.

 

I haven't been following... Is this a direct replacement motor? If not, the ECU might need to be reflashed with the proper parameters.

 

What year is your car?