OK I work at a car parts store with a couple really good mechanics and we're all stumped by this one. When I start my car and drive it a couple miles and then return to idle my engine starts to run extremely rich and runs rough. It shakes and you can feel it in the car, it actually sounds like a little diesel. But after I drive it another 5 miles or so and the engine is at max temperature the idling goes back to normal. I've swapped out the MAF, the upstream 02 sensor, new air filter, cleaned the throttle body, new engine coolant temp sensor (i have no clue why I changed this one), new spark plugs, oil and oil filter. When you hook it up to the data stream it shows that its running extremely rich and when you give it gas it drops timing to -13 and then goes up like normal. The fuel trim is going up normally. I've checked the pcv valve coming out of the crank case, no leaks. I'm at my wits end on this one could it be a EGR valve possibly not opening or closing correctly until its completely warmed up? Could it be the VTCS not opening correctly after its warmed up. I just changed the engine coolant temp sensor and when it cools down I'm going to see if that changed anything.
I have a knock sensor someone told me might be going bad but I haven't changed that yet since I cant really see how that could possibly be messing with my fuel ratios. The car only has 80k miles on it and the piston heads are spotless, it doesn't burn any oil and still gets exactly 35 mpg on the highway, which is the same as when it was new. When the car gets past this phase it runs like new, but it takes it a while to get past it. After all the new additions i've reset the ecm and let it idle for 20 mins to let it relearn with the new equipment. Any help would be appreciated.
Thanks, Kevin
I have a knock sensor someone told me might be going bad but I haven't changed that yet since I cant really see how that could possibly be messing with my fuel ratios. The car only has 80k miles on it and the piston heads are spotless, it doesn't burn any oil and still gets exactly 35 mpg on the highway, which is the same as when it was new. When the car gets past this phase it runs like new, but it takes it a while to get past it. After all the new additions i've reset the ecm and let it idle for 20 mins to let it relearn with the new equipment. Any help would be appreciated.
Thanks, Kevin