Ok for everyone who doesnt know i have a 98 ex coupe with d16y8 stock moter....Im still having issues with it so im going to explain everthing a littler beter to see if anyone will send me in the right direction...ok this is all i have done to the moter
-New timing belt and water pump
-all 3 acc belts new
-air filter
-denso plugs
-acdelco wires
-fuel filter-
-tranny service

My car also has 4-2-1 pacesetter headers on it...so here is what its doin..its worse when its up to temp or been idling for a few min...but its sluggish. like the power is being restricted...and like on the interstate crusing at 70 and get on it it just boggs and slowly accelerates...so im lost on what to do...this has been going on before i did all the mods listed above...im leaning more toward the converter but i dont want to buy one and it still do the same ****...and theres no engine light on...so im lost....any and all info appreciated...any more question just ask and maybe with the help of u guys we can figure it out...thanx and sorry for the book lol

 

bump please and also forgot to mention my gas milage is sucking...

 

Run a seafoam treatment, and check your IACV, it might fix your crappy idle, and the seafoam might fix youur gas mileage. Otherwise, it could be a bit more expensive to fix.....

 

Cam timing, or ECU in default mode.

 

Who did the Timing Belt, are you sure the car is timed right? The car was doing this before you did the header, plugs and wires? If you fuel milage went to crap it could be your fuel pump. Easy way to check that one is take your fuel line off on the in side of your fuel pump. Have someone turn the key to the run position(don't start though)while you hold your finger over the fuel line. If you have difficulty holding your finger over the fuel line your pump is good. Everytime you turn the key on in your car the fuel pump kicks on to basically pressurize the fuel line.
How many miles do you have on the car? The car should have thrown a CEL if you had an O2 sensor go bad, but that is a prime culprit for bad gas milage and crappy power, and I have seen Cats get clogged and cause problems but most of the time you won't see that tell 150K plus, and I know there is people out there that have 200K plus out there that say they have never changed theirs. Even though you don't have a CEL go to autozone or PepBoys(prefered) and ask them if they would hook up their diagnostic machine for you. They do it for free. You might have some codes in there and just not have the light.

 

my car has 116,500 on it and yes its been like this ever since ive had the car...the headers were on the car when i got it but i did have the timing belt and water pump put on by a local mechanic....my car is geting 21 miles to the gallon so i know something is wrong...

 

Like 1slowcivic and I said, timing, maybe the camshaft and crankshaft gears are one tooth off to each other. The new chain may have been put on assuming TDC was correct for both gears, repeating the error. Or the ecu isfaulty or misprogrammed. Have you considered taking thecar for a Tune? I mean a proper, instrument alignment?

 

Now define your 21mpg Is that hwy, aggressive driving, racing light to light? You have an SOHC with vetec right? Do you ever feel the vetec kick in? The lag in power can be caused by a lot of things, but I can tell you that an O2 sensor gone bad can cause your car to run rich, and that will cause the car to bog. A clogged cat could cause that, they have a bunch on ebay for like $20+. As I mentioned before I would go to pepboys, and see if they will run it on the diagnostic.

 

thanx guys im going to go buy my local auto parts store and see if its throwing any codes this weekend....and as far as the 21mpg i baby my car and thats goin 15 miles to and from work each day which is mostly highway miles....but it also seems to do it beter when its up to temp or been idling a few min....but if i just crank it up and go in the mournings its runs pretty good til it gets up to temp...

 

Definitely sounds liek a timing/ignition issue to me. Have you hit it with a timing light to make sure its within spec? How old is the dizzy? Tried a new cap/rotor/ignitor?