When I first start out driving the car, and come to a stop, in drive, the car begins to run rough. I can hear and feel the vibration, it’s very noticeable. I put it in neutral and it stops. As I load the engine with AC or use the electric windows it seems to gets worse. Then after driving for about 5-7 miles, it quits.
Primarily in cold weather, since it started 4 months ago. I do allow the car to warm up before driving.
I’m still under warranty, and have been to the dealer 3 times. Of course, it doesn’t happen when I go to see the dealer. But they did re-tighten the motor mounts. I don’t think it helped.
Is anyone else out there experiencing it? and What was done to cure it? Thank you.
Clean the MAP sensor with cleaner that is sensor safe. It is located in the intake plenum.
@knfenimore did you perhaps mean the MAF sensor? I’ve never heard of anyone cleaning the MAP sensor. Not yet, anyways.
MAF sensor sounds like it could be the issue. As an aside, you don’t need to let it warm up before driving, unless you are doing so to heat up the cabin. All that does is burn gas, when driving (gently) will warm it up faster.
Another thing to have checked is the Idle Air Control valve.
This valve allows the engine to idle depending on the load impossed on the engine. So for example when in gear this imposses a load on the engine. If the valve doesn’t compensate for this load the engine can run rough. As soon as the transmission is placed into neutral the load is removed from the engine and the engine smooths out. The IAC valve also adjusts the engine idle speed when an electrical load is asked for. This is because the electrical load is provided by the alternator connected to the engine by the belt. More load demanded from the alternator the more load applied to the engine. If the IAC fails to compensate for this load the engine can run rough.
IAC valves can be effected by temperature.
Tester
Could be quite a few things. Besides above, could be an EGR that is sticking slightly open. OP could try doing a hard acceleration (like a freeway on-ramp), and see if it stops having this symptom immdiately after. Even if gthe symptom returns, If so, that would be indicative of a sticking EGR.
The EGR circuit is an emissions control circuit and if there were a problem with it the Check Engine light would be on.
The IAC valve is an engine control circuit and won’t necessarily turn on the Check Engine light.
Tester
See if you can figure out how to replicate the problem consistently, then the dealer can figure it out. Leave it overnight at the dealer parked outside on a cold night. if that helps replicate the problem for the techs.
@Tester , yes, you are right, an EGR failure should turn on the CEL; however, there was a post here the other day where a similar problem turne out to be the EGR, fixed by cleaning the mechanism, and there was no reported CEL as I recall.
Whet year was the vehicle?
Tester
my follow up: The dealer changed out the front motor mount. The vibration has quit, but the weather in Okla has also warmed up, so I’m not 100% convinced that the problem was cured.
According to the dealer, the motor mounts are fluid filled. It’s possible that when cold, they stiffen up, passing the engine vibration into the cab.
The manifold absolute pressure sensor (MAP sensor) is one of the sensors used in an internal combustion engine’s electronic control system.
Engines that use a MAP sensor are typically fuel injected. The manifold absolute pressure sensor provides instantaneous manifold pressure information to the engine’s electronic control unit (ECU). The data is used to calculate air density and determine the engine’s air mass flow rate, which in turn determines the required fuel metering for optimum combustion (see stoichiometry) and influence the advance or retard of ignition timing. A fuel-injected engine may alternately use a mass airflow sensor (MAF sensor) to detect the intake airflow. A typical configuration employs one or the other, but seldom both.
MAP sensor data can be converted to air mass data using the speed-density method. Engine speed (RPM) and air temperature are also necessary to complete the speed-density calculation. The MAP sensor can also be used in OBD II (on-board diagnostics) applications to test the EGR (exhaust gas recirculation) valve for functionality, an application typical in OBD II equipped General Motors engines.