My check engine light, vsc warning and skid warning lights are all on and the car runs rough especially at an idle. Codes indicated a misfire on 3 coils. I replaced all 6 coils and spark plugs. A few days later all the lights are on again and it is idling rough. . This time, multiple misfires and mass air flow sensor. I replaced the mass air flow sensor. Again all lights are on and it idles rough. Can anyone help me determine what the problem is? The codes are multiple misfire and mass air flow sensor again.

 

My goodness. Did you replace those parts with Genuine Lexus parts, or aftermarket components?

 

Genuine Lexus parts.

 

Hmm, in that case, your dealer or mechanic needs to find out why and not charge you for the troubles it is causing you.

Assuming all the coils or sensors are good, it could be possible there is an air leak somewhere near the air flow meter such cracks on rubber tubing that is screwing up the air flow meter readings. If the air intake plenum had to be removed to get to some of the spark plugs, hopefully the dealer replaced the air intake gasket as well and tightened it down properly in the right bolt tightening order.

Have them check all your vacuum hoses too. Good luck. And don't run the car on fumes, fill up when it gets down to 1/4 full.

 

I just replaced the pcv valve, this did not fix my issue. So advice, could it be electrical or maybe a fuel injector issue?

 

Hi Donna, you're grasping at straws gambling and guessing rather than trying to find the root cause of the problem, and this is costing you money and inconvenience. Everything was fine before the coils and MAF, so the best thing is to take it back to the shop who did the work and ask them why it's running bad after they touched it. Good luck. Did you check the rubber tubes near the air flow meter?

 

I am doing my own repairs. I have been doing my own auto repairs for 25 years. .. I replaced the coils because there was a problem. Yes it is costing me money. But I'm doing exactly what the shop would do read the codes and making repairs.

 

Have you checked for an air leak behind the MAF? Get a spray can of throttle body cleaner and spray around the intake boot, base of the throttle body, along the intake manifold, etc while idling. If the idle smooths out and/or rpm picks up you have found your leak.