Car feels sluggish.

Ok so my 90 si doesn't run as fast as my 89 si did. A friend of mine said I may be feelign this because my 89 had a bumped up compression a bit from the z6 headgasket and had a 421 header on it. I don't think its because of that.

I am throwing a code, but its a 17, speedo sensor. My 89 had this before too and didnt cause any problems.

The previous owner of the car replaced the map sensor and said this may be the problem still.

The car runs fine, idles great, revs all the way to redline, doesn't smoke or anything, seems to be a strong motor.

What would you guys sudjest for me to look at first? I have a whole nother car for parts so I can replace anything i need to. Thanks guys.

i'm kind of having the same feeling with my 91 standard. it feels like it ran better a month or two ago. i'd suggest a basic tune up, oil change, and some of that injector cleaner stuff.

i talked to this one dude i know who only works on hondas and acuras and he told me that it can be sort of sluggish because of my axle because my cv joint is shot. i'm having a feeling its crazy talk. :dunno:

you might wanna try to start off with fixing the speed sensor,
its on the side of the head,below the distributor,
also,check to make shore your catalic convertor isnt getting clogged,
besides that,if your computer isnt throwing any more codes,you know there isnt any electrical/sensors gone bad,
make shore your getting a good fuel flow,cause if somthings getting clogged in the fuel system,your not gonna get the fuel you need when you hit high rpms,which needs the use of more fuel,wich will make your car run a little sluggish,
check your fuel filter,pump & the injectors.....

Basic tune up (fuel filter, pcv, cap/rotor, wires, plugs, clean the injectors, oil change). Worn axels/cv's can cause it to feel a little more slugish because of slack in it, but more than likly its not that noticable.

Is it sluggish only at a certain rpm? If its slow in the lower or higher rpms only then take a look at timing, may have slipped a tooth or somethng.

Nah, I think its slow all the way through the RPM band. I was thinking timing at first to, but I'm not sure anymore.

maby its just slower, some cars are just that way.

its heavier than the 89, that may be a reason

Tune up - fuel filter, injector cleaner, oil change cap, rotor and plugs.

Maybe you could swap your 4-2-1 header and the rest of the exhaust. Didn't you switch to a CAI? There may be some restriction if you're still running small pipes. It could also be that the car is heavier too.

EDIT: I just looked at the pics of the new Si hatch again and noticed the CAI (short ram) is on old car though you may have switched it over.

my bet still stays on your lower comp less mods

Turtle, No cai. That wasn't cold air on my 89 anyway. I'm keeping the stock airbox, its gutted and has a K&N. Works good and looks clean. Thats how its staying.

do a leakdown test on it and see how well your combustion chambers are sealing up.

How the valves sound? Mite need clearence. And do basic tune up like cap+rotor, plugs, wires, fuel filter.

well if you are throwing a code maybe your car feels slow cause it is in limp mode. Try to get that CEL light gone 1st.