bornwinnr

I just finished swapping an 87 4.0 into my 89 xj, which had a 4.0. The issue that I am having is that it idles fine, but sputters when I try to accelerate. If I floor it, it will eventually smooth out. If I let off and try to accelerate again it sputters. Any ideas?

Thanks in advance.

Jason248

did you keep the old sensors from your 89 motor?? if so try swaping out the throttle position sensor and see what happends

BlueXJ

TPS and O2 sensors are the main reasons for sputtering if the ignition is up to par. Idle would be the IAC.

syncview

Offtopic but: What exactly do you people mean by sputter?
Mine has started to do something like this: When ever I floor it, it kinda dies.. and then wakes up and goes BONKERS.. zooooom! Is this sputtering?

coyote121403

X2 on the TPS