Yesterday I went out to start the car and it ran really rough for about a minute, the check engine light came on but no warning message. Then it smoothed out and ran fine. Same thing all day whenever I started it. This morning, same thing. Runs rough, then smooths out and runs fine. Anybody know what this is all about?

 

First thing, stop by one of your friendly auto parts stores that will read you OBDII codes for free. That will tell a lot more than us guessing.

. . . but . . . never being shy about guessing on someone else's car I would suggest starting with cleaning the MAFS and throttle body.

The codes will provide better advice.

 

I'll check at the auto parts store for a code read, thanks. As for the MAFS, that gets cleaned with every oil change and that was done recently. Re the throttle body, how often should that be cleaned?

 

chaz, was there considerable noise upon starting as well from the engine...rattle? Just asking if your tensioners were replaced in the past, that's all.

 

OK code was for multiple cylinder misfires. Re. Tensioners, I don't know if they were replaced before. What's weird here is that it started and ran really rough the engine light came on but it didn't go into restricted mode. I did a BG Throttle body service this afternoon. Not sure if that's the problem but it can't hurt. I had this happen about six months ago only then I got error code on the odometer screen. This time just the check engine light.

 

Opinion.

Multiple cylinder misfires sounds like tensioners to me.

Doesn't the car have VVT which would try to adjust the timing to correct a loose upper secondary chain?

Misfire and timing go hand in hand don't they?

Just guessing on the VVT and why it smoothes out after awhile.

Again just my 2 cents worth. You'll get your answer from this forum.

 

Not sounding good... get the codes specifically put on here, im wondering if it is a single bank or both

 

It's both banks

 

They didn't give me the precise codes...just said it was multiple misfires, 1,8,3,7, etc. The print out they gave me said:

"Check engine Indicator will illuminate when a fault it detected on the second drive cycle. Only catalyst-damaging misfires, certain internal ECM failures and Controller Area Network (CAN) faults will illuminate the Check Engine Indicator on the first drive cycle. In certain circumstances, the Message Center will display fault warning information simultaneously with Check Engine Indicator or when fault is detected on the first drive cycle. Also, in certain circumstances, the Amber or Red MIL simultaneously with the Check Engine Indicator and Message Center indicating the priority of the fault."

FYI: I got no fault warning info on the Message Center and no Amber or Red MIL above the Message Center.

 

Pxxxx codes might help . . . a lot.

Both banks . . . not tensioners. But if replacement unknown I would sure put inspection high on the things to do list.

Next guess is, of course, ignition. Both banks, all cylinders goes back to ECM. More likely connection than module itself.

How many miles? Need spark plugs?

 

57K miles. Also vin ends in A13402 which if I am correct is in the range of the tensioner failure issue. Again weird thing is that it straightens itself out in less than a minute.

 

Also, car runs strong, great acceleration, etc.

 

without the Pcodes, and based on prior history, its sounds like it may be either ECM, MAFS, or throttle body, or wiring/connectors between and around. Chaz, see if you can get the actual Ps, they are more likely to narrow it down more than what you were told.

 

I'll go back and get the codes today. However, since I had the BG Throttle Body service Wednesday, it has not happened again. I'm now guessing that was the issue.

 

the codes may still be there in the computer, pending how many successful cycles you've put it thru. You'll be a step ahead of the game with them and doing a little investigation here just in case it happens in the future, you'll be prepared with a plan.

 

Good Point H2Oboy. The other thing I learned in this process is that my vin# is withing range of the tensioner problems. Guess I'll get that checked soon. Anybody know how much it should cost to have that checked?

 

You can check it for 'free' if you're willing to open her up.

 

Pulling a valve cover is not difficult. I found the right side easier than the left. Total tools needed is a $10 set of 1/4" metric sockets. I removed mine and reinstalled without changing the gasket and have experienced no leaks.

If the tensioners are the white, now orange, plastic ones plan on replacing them.

If you are going to have someone replace them for you plan on an hour to check and 4+ hours to replace. It took me 4 hours total to replace the tensioners and I was cleaning up the engine as I went. I had never done that before. Most independents will quote $800 including parts. Parts are $150 without gaskets, $225 with. A mechanic will insist on new gaskets and I do not blame them.

 

Test Point,
Thanks. I might give that a shot. Doesn't sound that difficult.

 

Testpoint,

From my understanding I thought my 02' had new generation tensioners...yet you changed yours?