RPMs drop suddenly.... need help figuring this one out.

[DeLo360]

Between 1.5 and 4 thousand RPM as i'm driving in any gear, the RPM needle would just fall about 500 or 1000 RPM and the car would studer and jerk forward as the needle catches up to were it used to be. The last time i had this happen, it ended up being a blown coil but that threw a CEL. How can i go about diagnosing this problem or checking the coils? Thanks guys i have no idea what to do on this one.

Dave

 

[link16]

Any other symptoms? Rough idle? Any knocking or ticking? Long starts? Personally I need more to diagnose.

-Alex

 

[91dsmpossible]

actually my car did that acouple times today. when i pushed the clutch in to shift it would die and it threw a CEL everytime. U think mine could just be my coil or maybe somethin else? Sorry bout the thread jack.

 

[link16]

I would test it, Take it to an Advanced Auto or whatever you have there and have them pull the code. It sounds like a starter or bad coil.

 

[DeLo360]

Any other symptoms? Rough idle? Any knocking or ticking? Long starts? Personally I need more to diagnose.

-Alex

No other symptoms at all. Although when i first noticed this, it was two days ago on my drive back from the beach. I pulled off the highway just to make sure everything was ok. When i turned the car back on my battery light came on. I noticed my lights were dimming and i got really worried that i wasnt gonna make the trip back. However, the belt that powers the alternator has been very very sqeely lately and the battery light problem got fixed the second i got back on the highway. The lights instantly returned back to their normal brightness the second i reved my car up... and by the time i made the trip back the battery was charged and all was well except for the problem i described at the begining of the thread. I've since then replaced that belt, and no power issues have occured. Although, now that i think about it the car first started doin its RPM drop thing while i was using the cruise control. The cruise control would work fine for a bit and then it would turn itself off. So i kept turning it on, and in a matter of 30 seconds it would turn itself off again. I did this a few times and the RPM drop thing started after that point.

 

[BigRand]

Okay if you want to check your car for spark,

I'll give you an easy way however be forwarned that you could be shocked by the spark from the plug wires.

First off I want to ask you if your car exhaust note sounds different, or more like a subaru?

If so then it is probably a timing or spark issue......

anyways to check your coil, simply pull one plug wire out at a time and listen for a change in the exhaust note, The change should sound like the car is missing.....if you pull one and the exhaust note doesn't change, then thats usually the cylinder that isn't getting spark.

This happend with my MSD blaster coil, and so I went back to stock and everything was just fine.