xplane

ok this is starting to weird me out. my car seems to change how much power it makes on a daily basis.
it seems to have 3 major moods or something. 1. if I go out and start the car hit the gas and she goes well what i would call normal, pulls good but cant break the tires free. 2. hit the gas and i wont pull its own butt. 3. hit the gas and its one of the two above choices or this is my favorite. goes like hell, burns the tires off, roars like hell over all just f'ing awsome. then the next day it will go back to being a weak *** little wus. WTF? dont seem to be weather dependant or specific. it just kinda decides. no changes just shut the car off and go inside, in the morning i come out and start it up, hit the gas and wonder what im gonna get today.

Edit: it does seem to coincide with how smooth the car runs tho. the more power it has the rougher it runs. at its best it will die once or twice at stop lights. and when it is super weak it ides at 500 exactly and dont bob or nothing.

Project: 85 2.8 bird

idles @ 500???

daves12secV6

iTrader: (3)

check o2 sensor,ones for our cars are only 19$'s for a bosch o2 from auto zone,a dying/failing o2 sensor can account for bad performance/gas milage,and the ruff idling etc.
when i first got my rs it ran great but like u say every now and then it would be down on power.turned out it the maf sensor going crazy internitantly

one last thing next time the car acts up,even if it dosent throw a check engine light.try to pull codes anyway ive been able to pull codes on some cars without the light being on

xplane

Yes it idles at 500 normal.

O2 sensor is only about 1yr old and has well under 15,000 miles on it.

The MAF is about 6 months old so that shouldnt be it.

When you say bad performance/rough idle is caused by those two things that is what is odd abbout this, the car performs better when the idle sucks but when the car idles nice and smooth it sucks on power.

Another odd thing is that the performance/idle quality changes from day to day/week to week and it always follows the same pattern.

The car idles smooth= no power.

Idles kinda choppy but no stalling= it is able to easily keep up with other traffic but not able to easily out run other cars.

Idles like crap, surges, stalls= goes like a bat out of hell.

again this changes from day to day and some times it will not change for a week or so.

Edit: This is not just me fooling my self either every one i hang out with notices it. Most wont race me when it is idleing crappy but if the car is idleing smooth its easy pickings.

daves12secV6

iTrader: (3)

idling liek crap is prolly due to the fact its running rich,liek i was once told just because u replaced a part recently doesent mean it isnt bad again.most replacement parts are reman junk or low quality ****,unles su get liek delco parts etc,al that off brand **** most parts places carry is just junk

yupitsdadsbird

ain't that the truth. 6 sets of motor mounts, 4 water pumps, 2 a/c compressors, 2 clutchs and that's all I can think of in just a year.....
it's like mcdonalds over outback

Drew

iTrader: (58)

Check your codes, it sounds like you've got an intermittent issue, and it's probably sensor related. If a sensor is failing, or has failed a code will be set. If the codes come back clean start diagnosing it with the basics, got fuel? got fire?

Do all your troubleshooting when the car isn't running right. Keep in mind that the car might be running better when the issue is occuring since it may be in limp home mode bypassing the system that is malfunctioning.