acceleration loss (long)

hey guys just signed up to the forum, i've got an interesting problem. i tend to ramble :D i'm sure a similar one may be posted somewhere else but i feel mine might be unique. basically the car runs GREAT cold, has a real strong sounding idle, etc. when the car warms up (not necessarily all the way) about 10 minutes of driving. it loses a lot of power. not tonnes though, just the low end. everything over 3000 rpm's is fine, but its annoying trying to stay in that powerband. last time i checked our cars didn't have v-tec, but thats what it sure feels like.

the only things i've done to the car is removed the exhaust resonator, performance muffler, and a k&n filter. i'm running good oil that stays clean, i've cleaned out my intake & combustion chambers, put in new plugs, wires, pcv valve, fuel filter within the past 20000kms, and im sure i'm forgetting something. no check engine lights whatsoever, but once i had a mass air flow sensor code, but cleaned it off with brake cleaner and it went away. 2 of the coil packs got corroded a while back, but were cleaned off and all 3 seem to be producing good spark.

i swapped out a different o2 sensor (used) with moderately improved results. my fuel economy never really is that bad. the window sticker on these cars says 42mpg on the highway is possible, i usually see 27-29. one thing i tried to see if i had a clogged catalytic convertor was removing the pre-cat o2 sensor and driving around with it out. didn't notice a real difference. it was funny to hear how terrible the car sounded with a whole in the exhaust though, hahah like a real poor running 4 cylinder mustang. one more thing i checked with a tech 2 computer at my old work the fuel tables. the computer said -14% long term fuel trim. which means i was running rich for quite a long time, but not enough for a check engine light to come on. i'm running 87 octane gas with 0 degrees knock retard...

anyways i'm not sure what more information i can provide but thanks a lot for any help you guys provide.

welcome to the forum. First of all, brake cleaner on a MAF sensor is a really bad idea. If you didn't trash your MAF (which would explain your problems) then just make sure you use precision-electronics cleaner next time.

My 1st guess was MAF because of how you said you cleaned it, but also since you were running so rich so long, it may also be possible that you could have a bad intake air temperature sensor, or clogged / leaking fuel injectors (very likely cause).

hey, thanks for the quick reply, and the welcome! i guess i heard wrong on the best way to clean the maf... it looks like it may have been dropped before i had it because theres a 1 inch crack in the plastic harness area. as to the fuel injectors being clogged, i did have them flushed about 10000kms ago, i forgot to mention that. that doesn't rule out that they might be leaking though. very good idea on the iat sensor, how would i go about testing it? i do have a multimeter i've just never played with it. any way i can test the iat or the heater oxygen sensor with it?

wow forgot i posted this... any one with any ideas?

almost ironic you find the post exactly 1 year ago! :rofl:

as for your troubles, :dunno: what ride said back then was pretty useful... how much heat would you say is being applied? I notice my trans eventually starts to act up after a good day of hard running... but as goes the car... it just depends if the low end wants to work great or not.... But these days in 104F heat =p its been doing just fine...

back then, hahah :grinyes:
104 degree heat? yikes. we've only been around 80 degrees here.
as for the car it doesn't heat up all that much, stays where it should on the temperature gauge.

i see you have the same car, you might want to check into the cooling fan override. caspers makes one, but its very expensive. i can't find all that much information, but some people can figure out how to do it themselves.
anyways. i think the problem (after a year) heheh might be the muffler.
the guy at the exhaust shop pretty well lied to me. although i knew that for a long time when i undercoated the car and saw the muffler he put on wasn't really what he said it was.

it was claimed to be a hooker muffler, which don't come cheap. but its actually a black cherrybomb vortex muffler. y'know, the cheapest of the cheaps. i did a little reading and some people say their low end gets a little lost after putting it on.

strange thing is it only happens after the car is at operating temperature. when its cold its got tonnes of get up and go. also i just put on a warm air intake, so the heat lag comes into play there as well..

oh, and i did change out the maf sensor that i cleaned with brake cleaner, and got a new o2 sensor as well