frends car, after he replaced both since they failed, it feels underpowered, no CEL, clutch doesnt slip, any ideas
is it a 2.4?
Year of the car would be rather helpful as well.
[generic troubleshooting]If it’s older and has a distributor make sure timing is set properly[/generic troubleshooting]
2.2 eco 05
back when I had ign. problems I replaced a lot of parts on my 2.4
Turned out that my NEW plugs were crap.
he has platinum plugs in there which i wouldnt put it but when i looked up the plugs the ones that came up were platinum, i figured theyd produce too much heat and make the car run shittier, which ive experienced on customer cars who swap out the platinums for cheapies
I think most of my engine trouble stemmed from the crappy turbo kit 
try j-body.org ?