Intriguing problem - engine rough idle & hesitation - P0300
Hi everyones, Im newly registered here after a couples year of reading helpfull tips here.
This forum has been helpfull since I got my 2004 Rio RXV with/AT two years ago.
After a couples day of search here, I did not find a very similar case to my problem.
# 1 Symptoms/problems
The car as 85,000 km on the odo (50,000 miles).
So, here it is...It started in beginning of August 2011..rolling on the highway by a beautifull summer noon, speed was around 60mph / 100 kmh then I sense a sudden hesitation in the car motion.
It was for a very brief period like 0.1 second. Like if I would have very rapidly have let off pressure on gas pedal and then reapply it.
It did it 3-4 times during the 75km trip home.
Let me tell you I was stressing as my newborn was in his childseat and with no cell phone on board.
My girlfrien used the car intown for 1 weed until the Check engine came on.
I sent the car to my thrusted mechanic garage, he read the codes P0302, P0303 ( misfire cylinder 2 & 3)
So I told him to suggest me something...we opted to start with the spark plugs first and also erase the codes.
The car ran fine except for still small hesitation while rolling.
One week later We are now mid August... my girlfriend used the car to go to his parents in the neighbor town ( again 75km ).
Almost arrived at destination the car started to hesitate like never before...a lot of stumbles and ckeck engine lighted again....but this time the engine was running with the computer in safe mode so not much power.
Very frighting when it happen on the highway with a kid onboard.
There a friend mechanic read the code and still P0302, P0303 ( misfire cylinder 2 & 3). So he tested the plug wires with a splash of water just to find they were no good anymore.
So changed the wires....damn problem was still there engine was running very rough. So we did changed the coils pack....that did the job car ran great.
So, coil, wire, plugs are changed, no check engine. My girlfriend decided to come back home. Midway (km 20 of 75 ) Hesitation again...Damn and Damn !!...the mecanic told me the only thing he can think of is bad gas.
I did put a can of gas treatment in thank with fresh gas.
Since 1 week from now the car is acting stangely, sometimes it is running ok than hesitate a bit. But 4 days ago it started to idle very roughly when in D or R. When arriving at a stop or red light, SOMETIMES the engine want to stall. Then a couples minutes after the check engine light on.
When it want to stall if i put it in Neutral and give it a bit of gas is help to keep the rev. If i dont do that , the engine keep reving slower and slower with a lot of vibrations ( like a harley davidson engine on idle). Keep in mind that it is an intermitent problem.
The check engine code is P0300 (multiple cylinder misfire )
I brought a spray can of Throttle body cleaner that i used completly through the mass airflow as per the recommendation of my thrusted mechanic....did not seem to help a lot but it seem the problem bay be lessen than before.
So he suggest me to unplug the car battery to erase the code..and possibly reset the computer. My mechanic suspected the bad idling is comming from the SAFE MODE in the computer.
That fix WORK. Since the 2 last days, car go well for 4-5 km then bad idling start and car as difficulty reving and has no power, I just reset the computer with the battery unplug method then Im good for another between 1 to 20 km... again and again.
Now im seeking for help from the community.
Thanks in advance.
Last edited by DANBAT; 08-31-2011 at 11:32 AM.