Greetings! My RR has hesitation and vacuum "sounds" coming from within. I tought it might be a bad plug/plugs so I changed them. None were fouled with oil. Also tried a can of super injector cleaner in case it was dirty injectors. I did find a worn out (partially melted) breather hose from the plenum to the cylinder head cover, so I replaced that as well. She seems to run okay in the morning when cold, but on next warm start she bucks and has no acceleration. Also check engine light is on. Any comments, fixes, etc would be greatly appreciated.

 

well, If you don't have an obd scanner, many auto parts stores will read the codes for you for free. My bet is that it is a dirty or bad Mass Airflow Sensor, but check the codes first. Too expensive to just guess.

 

It could be so many things it is hard to tell without the codes. Get them read and then come back with what they say. I am with Scott, it could be a dirty MAF, or maybe even O2 sensors, or just a bad connection at the MAF. Let us know what you find out from the parts store.

 

Latest developments. I had the oil changed and the valvoline quickie place had a code reader. The RR did not throw any codes out but I still have a check engine light. It is running great when I start from cold but still having the hesitation "burps" coming from the engine when I start it warm.

Will an MAF problem normally throw a code? I think it may be time to consult a mechanic. On a non-related problem: Is there any way to default my A/C vents to only blow out of the top registers? I think I have the bad servo motor problem and I know the fix is expensive. I live in Naples, Florida and I could care less about haaving the vents switch. I just want max A/C coming out. I know I am losing a lot of cool air because I can feel the drafts down below. Yes I am getting the !book warning on the temp control panel. Any advice will be appreciated.
THANKS!

 

I used to have an M5 with, I believe, 2 MAF's , so I know a little. It looks like a tube with a thin wire in the middle, right? I believe the wire heats up and burns bad particles flowing in. Isn't the procedure to clean the wire and see what happpens?

 

The wire does heat up, but it doesn't clean anything.... There is a temp sensor in the front of the MAF where the filter box is that measures the intake temp. The ECU then heats up the MAF wire to a specific temperature. The air flowing past it will cause the wire to cool, the ECU measures the temp fluctuation on the wire and is able to determine the amount of air flowing into the engine. There is a proceedure to clean the MAF. 1. Go by MAF spray 2. Take the MAF sensor unit out of the vehicle 3. Give it a nice spray inside, and allow it to thoroughly dry 4. Reinstall the MAF sensor in the vehicle.

If the servos are fried, then they are fried. The only thing you can do is turn the fans to a very low setting that will assist the servos when they move. Move the fan position up and down to see if you can some how get it to move. The book symbol means something of course is wrong with the HVAC, most likely its the servo not responding, or giving incorrect readings. If there is a check engine light, there will be a code. The ECU will not turn the engine light on, unless there is a code present. The scanner the mechanic has may not be able to read w/e code its throwing, even though that is doubtful. Are you sure its not the "service engine light"?. You can also get a scanner that can read the live engine data. You will want to specifically look at the amount of air the MAF sensor is showing entering the engine.

 

It is the service engine light. What does that mean? I took it to the mechanic it goes in Thursday for a check. He thought it might be the MAF or the temperature sensor because it only happens when it is hot.
I will let you know the outcome.

If I can reach the vent servos isn't there a way for me to hand crank them to be just blowing out the top vents?

 

service engine light means nothing. Just take out the bulb. How many miles are on it? You mentioned changing spark plugs. What about the wires? Fuel filter? Does it run hot? Does it use any coolant?

 

Here is the latest in my continuing saga of acceleration problem:

Just a quick recap. My RR has been having problems with misfiring after a warm start. First drive of the day is all systems go. If I drive the car for 10-15 miles and the engine is warmed up, I park and drive again 5 minutes later the engine sputters and misfires, sometimes stalling and forcing a starter fluid shot to re-start. As soon as the engine smoothes out and I drive at some reasonable speed power returns and the RR runs nominally.

I have replaced the plugs, plug wires and my mechanic has put her on the code reader. He is thinking I may have bad coils? My understaning is that coil replacement will be $500-$600.

Anyone have any ideas??

Here are the codes he read:
PO303- Cylinder 3 misfire
PO300- Random cylinder misfire
P1177- Fuel air metering

I installed a new battery last month and in the process caused a leak at the radiator cap small (overflow?) hose. The car still runs at the half way line on the temp gauge, although a little over when stopped for a long time but it has always done that. I only mention that for full disclosure.

Tell me someone has a fix that does not include new coils.

Thanks, in advance, for any help from anyone.

 

Are you running premium fuel?