General Maintenance & Repairs - bouncing rpm and speedo needles... WTF?
07-21-2012, 03:09 PM
last week on my way to a couple car shows I noticed that my rpm and speedo gauges started bouncing randomly. when it would do it i also noticed that the car would seem to miss. when it would happen i would rev the engine and everything would go back to normal. couple miles down the road it would happen again. this time i threw the car into neutral and revved causing a huge backfire. car cleared up once again. couple minutes later got a service engine light. scanned it and came up with a maf and o2 codes. cleared the codes. since then the needles will still bounce randomly with the miss (can also hear it in my sub when its happening??) and yesterday it threw a cam positioning sensor code. all this seems electrical yet i cant find anything wrong. anyone else ever had this issue or have any ideas what to check? thanks
07-21-2012, 03:58 PM
My car was doing this a while back, gauges going crazy and engine missing. Can't remember if the SES light was on or not. It was a bad connection at the battery. Have you checked your battery terminals for corrosion?
07-21-2012, 04:04 PM
Thought it might be something with just the speedo and tach but because it's having the misfire/ back fire stuff it's sounds like one of the sensors are bad and getting false readings everyonce and a while and causing these "hiccups". Do the codes tell you which side O2 sensor is bad? Right or left? Or is it just a generic 02 sensor code? Have you taken off your lid and checked out the maf? Could the maf maybe be filthy?
07-21-2012, 04:16 PM
LOW VOLTAGE! if the pcm is starving for power it will reset the speedo cluster partially causing bouncing needles and also begin to miss. Check your connections, alternator, and battery. Usually a bad connection on the alternator or a bad alternator all together.
07-21-2012, 10:36 PM
both o2 codes. the day it started i lightly sprayed the engine compartment down with the hose. it looked like i lived on a dirt road lol. my engine bay is usually very clean. i degrease and powerwash it twice a year with no issues. i didnt soak anything just a quick spray. i think im leaning towards the alternator. maybe i screwed it up. guess ill test it but it doesnt happen all the time just randomly, ecspecially when i first start the car. is there an "upgraded" alternator if it needs to be replaced or should i just stick with stock?? thanks guys
07-22-2012, 08:45 PM
looks like i need an alternator.... any suggestions where? also what am i looking at spending roughly?
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