QuestionThe engine service light came on. I was told by a mechanic that the EGR valve on my 1997, 3.8 liter, v6, tested defective, but he said that the real problem is that the upper intake manifold has a clog in some part of it near the throttle body. Another mechanic told me that he tested the problem and the testing divice said that the EGR was bad and so I replaced it. Now the service engine light is on again and I'm wondering if the first mechanic was right all along. My question is that when the mechanic does the diagnostic test and it shows that the EGR valve is bad agein, after I bought and installed one for $219.00, should I now put the new upper intake manifold on it? Thanks for your help.
AnswerHey Ken
A new upper intake shouldn't be needed. Many times, you can clean these pieces out just as clean as they were when they were new. I've done this many times, for 3.1's and 3.8's. The question is whether to clean the intakes and throttle body before changing the valve. The answer of course is yes, but be careful not to wait too long until replacing the valve. It would be beneficial to do them both at the same time. Though I know this would cost a lot more.
Your ECM computer will get new readings after a new valve is in, and you may notice the "service engine soon light" on for a couple of starts after the change, but should then go away. The throttle body will need to be cleaned as well, this is done quickly, easily and cheaply. You'll likely notice a bit less fuel economy just for a day or two, until the speed chip calibrates itself again.
After all is said and done, you can keep the throttle body clean by making sure you keep a clean air and fuel filter on the car, these are inexpensive items that will save a lot.
