Why is my cars engine poulsing from 1k RPM's to 3K RPM's????

Amber · Post by **Amber** » December 3rd, 2005, 8:24 pm

I have a 1993 MX-3 V6 GS and i just got the oil and filter changed last weekend! But ever sence then whenever i go to start up my car it starts to rev its own engine from 1K RPM's to 3 RPM's not fast but slowly! DOES ANYONE KNOW WHY ITS DOING THIS!?!?![/b]

shawno · Post by **shawno** » December 3rd, 2005, 8:38 pm

hey yea my car did that to it would feel like the cluthe to slipping but it wasnt. So i changed my plugs, wires and cat and rotor. and it all went a way. but the wires are expensive tho like 130 plus.

MX3 GSR for dummies · December 3rd, 2005, 9:30 pm

sounds like it could be a couple things but before I illaberate, a little more info....is this reving occuring when your car is in idle or drive?

Amber · Post by **Amber** » December 3rd, 2005, 11:30 pm

My car only does it when its in idle! When it first started doing this it usually stoped after it was warmed up! But now it just wont stop!

jschrauwen · Post by **jschrauwen** » December 4th, 2005, 12:10 am

Like GSR said, it could be a number of things. It may be that it needs an accurate TPS adjustment. How's your coolant level been lately? Has the car come close to overheating lately? Perhaps the coolant thermosensor is unserviceable. Even an air pocket in the cooling system could work it's way to the area of the thermosensor whereupon it would not be in contact with the coolant getting the impression that the engine may be cold and therefore it would bump up the idle and then increase the coolant flow where it would come in contact with the thermosensor again and then re-adjust idle back down to normal again. And this process could go back and forth continually. There may be a couple things at play here. How handy are you around the engine?

Amber · Post by **Amber** » December 4th, 2005, 12:36 am

A while back my car over heated and i put a new radiater and the coolant was low! I dont know if that has any connection with whats happening now! And when i checked it tonight it was low! And i have 3 older brothers who are great at working on engines and my dad ........Soo......

Grants · Post by **Grants** » December 4th, 2005, 12:41 am

I'm guessing a leak in the intake.... classic symptoms. Check for cracks in the accordian hose after the MAF.

jschrauwen · Post by **jschrauwen** » December 4th, 2005, 1:02 am

Grants wrote:I'm guessing a leak in the intake.... classic symptoms. Check for cracks in the accordian hose after the MAF.

Dohhhh, there I go forgetting the obvious.

Amber · Post by **Amber** » December 4th, 2005, 1:43 am

Thanks ill check that and then ill check in with you later!

FlyVFR · Post by **FlyVFR** » December 4th, 2005, 2:11 am

Sounds like your car's idle is in the "hunting" mode. Did the "Check Engine" light ever come on? If so you may want to do a diagnostics readout.

Some things to check in accordance to what was posted by other members already:

1. Idle Switch
2. Air leakage ( vacuum & intake )
3. Air Cleaner element
4. Air Flow meter
5. Ignition
6. Spark Plugs

I had a related event one very cold morning on the way to work a while back. I never found out what caused it because it stopped doing it after the engine warmed up and never returned.

Good luck!

Amber · Post by **Amber** » December 4th, 2005, 2:19 am

I had a related event one very cold morning on the way to work a while back. I never found out what caused it because it stopped doing it after the engine warmed up and never returned.

Good luck![/quote]
Yeah thats whats happening to me! It finnaly stops pulsing after its warmed up! But my heater stoped working it jsut blows cold air out! So im wondering if my thermastat is out!?!?!

FlyVFR · Post by **FlyVFR** » December 4th, 2005, 2:33 am

Check the coolant level and for any leaks. If it's leaking coolant from the water pump it will need replacement. If the water pump is faulty, might as well have the timing belt changed also if it's withing the interval to do so. ( every 60,000 miles )

jschrauwen · Post by **jschrauwen** » December 4th, 2005, 2:35 am

Amber wrote:I had a related event one very cold morning on the way to work a while back. I never found out what caused it because it stopped doing it after the engine warmed up and never returned. Good luck!
Yeah thats whats happening to me! It finnaly stops pulsing after its warmed up! But my heater stoped working it jsut blows cold air out! So im wondering if my thermastat is out!?!?!

Ok, there we go. Possible thermostat stuck closed and possibly air locks within the coolant system that would affect the coolant thermosensor. A lack of circulating coolant means that the TB is not getting warm coolant running through it either which on extremely cold mornings can make a big difference.

FlyVFR · Post by **FlyVFR** » December 4th, 2005, 2:37 am

An open thermostat would cause the heater problem you describe if you only drive a short distance.

FlyVFR · Post by **FlyVFR** » December 4th, 2005, 2:43 am

jschrauwen - I did not see your post before I posted the previous. I agree with you on the closed thermo. on short distance. But it would probably overheat on long drives, I guess