I have what appear to be droplets of oil that are collecting on my bumper and back of the car which I assume is coming out of the tail pipe. I just had the car in the shop because the injection pump was messed up and it was running to rich. I checked the oil last week and it was fine. 1900 miles and it had not used any oil. Now it was down a quart and I noticed it on the back of the car. Any ideas?