when my car is parked or stoped the rpm is at 800rpm then all of a sudden the rpm meter will drop to 600rpm then right back to 800rpm it does it about every 5-10seconds. why does this happen?and should i take my car to a mechanic? my car is a 97 tib fx.

 

Could be clogged fuel filter causing variations in fuel pressure. Bad plugs fouling up. dirty fuel injectors causing improper atomization of fuel. Bad Idle air bybass valve not letting in enough air...etc..etc..etc..

i would start with the basics.
When was the last time you replaced the Fuel Filter?
When was the last time you checked/replaced your spark plugs?
When was the last time you used fuel injector cleaner?

Does it do this when hot or when cold or both?

 

TPS, very common on elantras and tiburons!

 

Have you got a system in your car?

Same thing was happening to me on my 97 accent, then the alternator died smile.gif

I charged the battery and replaced the alternator and now she is just fine. I would recommend just charging your battery (assuming it needs it).

Hope this helps.

 

he's only got like 37~38K miles for 97 which is VERY VERY LOW.....
anyway, sometimes RPM tends to go down when the A/C kicks in, like for defrosting window or whatever.....when it doesn't need it RPM comes back up(A/C light remains on)

you know what i mean......
should be ok

 

Funny this post is here. Last night I was outside re-installing my dash (just got painted) and had the car running cause it was like 30 degrees outside and for awhile it was running fine then all of a sudden it dropped down to like 500 rpm's then stalled I started it back up again and it was sitting on 500 rpm's and shaking like I was in the cold I hit the gas and it would either stall out or tach up all threw out this I heard the air filter chugging and the exhaust putting then I restarted the car again and it was gone and there was no cel either I wonder what the hell it was any idea's.

 

thanks for all the advice but the winer is random i need to get a new fuel regualtor and two of my spark plugs were cracked so i replaced all four of them with a better brand thanks again.(MySilverTiburon my car only has 36,689 for a 97 tib) and jaws99 i hope this helps you two but you should take it to be looked right away.

 

Yeah considering I only have 18,000 mile on it and it also has some kinda knock coming from by the under drive pulley well, after Christmas I know where me and the Tib will be rolleyes.gif