first, as far as engine mods & what kinda stock crap i got, here's what i got...

-injen cai
-cattman Y
-apexi WS cat-back
-CA spec
-5 speed

now, i bought the car back in dec 04 in Oceanside CA, were the elevation was low and humidity was high. i drove it up to Victorville CA were elevation is high and humidity is low. the reason i'm bringing up these things is because i think they may be contributing factors to what happened next.

after about two weeks of driving, while going full throttle i felt the car start to lose power and immediately after the SES light would flash at me for like 30 seconds then turn off. obviously when i saw the light come on the first time i took my foot off the gas. it happened a few more times and each time after the first, when i felt the car start to lose power, i would take my foot off the gas, but i still got the flashing SES light. after a few times, the SES light stayed illuminated. i changed out the plugs with NGK coppers. about a month down the road, same crap. this time i changed em out to Denso Iridiums thinkin maybe that'll make a difference. these lasted about four months then same thing. this last time, i changed em out to one step colder NGK Iridiums. these have lasted me about a year, or 20k miles. i'm starting to feel the loss in power some times but i take my foot off the gas before the SES starts to flash.

also, today, while i was driving about thirty mph in 2nd gear and i almost rear ended someone and i locked up my tires along with the crank since i locked em before hitting the clutch. i fired my ride back up and at the next stop light i was idling at like 1500 rpm (the ac wasn't on and the engine was already at normal ops temp). thats the first time it's ever done that and i think the one step colder plugs are to blame, not sure though. after another 50 miles of driving, blipping the throttle, and turning the ac on and off, the rpms finally settle back to there normal 600-700 rpms.

it seems like these NGK Iridiums lasted a good amount of miles, but after today, i'm thinking the colder plugs may not be correcting the problem, just hidding it. as far as gas mileage, i get about 25 mpg, and i never see any smoke out the tail pipe. i kinda have an idea why the idle rpms were so high but i don't see how the lock up initiated it. i'm gonna need to buy plugs again but i'm not sure what kind i should try next. any advice would be helpful. thanks...

 

Stay with stock plugs...change your coils they're bad.

 

what makes you think its the coil

 

You have a 99 and they're notrious for going bad on that year.. Also the symptoms you noted are indicative of bad coils.

 

how would i figure out which one it is???

 

Check your ECU codes. Most likely it's more than one.

Check the FAQs/Stickys, there's a post that explains the process.

 

thanks for the info

 

not exactly related, but... doesnt the injen cold air intake actaully take in hot air from the engine. you may want to change that for better performance in the hot and humid wether you may or may not have from time to time.

i dont think its a problem just something to note.

 

the injen is not a true cai, but i have a heat shield on mine and i also removed the plastic cover underneath it and that made a world of difference as far as throttle response. i'll call it a warm air intake.

as for as the plugs, i really don't think i could've driven for 20,000 miles with no drivability issues if i had a bad coil(s). NmexMAX, no disrespect, but personally, i think this high elevation and low humidity is overheating my plugs, causing the spark plug ground strap and center electrode to act as a "glow plug", which is then causing pre-ignition and detonation. thats why i tried an iridium first (my condition improved, but came back), then i tried one step colder iridiums which for the most part cleared my problem.

i guess what my real question is, what effects will you see from running a colder plug without nitrous or s/c???