Quote
I'd check the plugs and possibly replace them.


Good first start!

These engines are VERY picky about which plugs they use.
If the engine came with NGK's, put NGK's back in it.
A lot of these engines came with Champion plugs, and
work best with Champion plugs.
The ion sensing knock control spark system is very finicky
about plugs.

1995 Trooper LS auto 3.2 DOHC /w SOHC intake
1989 Trooper 2.6 auto
1989 I-Mark RS DOHC 1.6
1991 Stylus XS DOHC 1.8