Here's another question which has been asked at least 50 times in the last 12 months. In fact, I just answered a similar question this morning!
For the most part, modern vehicle electronics are not bothered by RFI, especially air bag and engine control systems. It isn't you interfering with them, it's them interfering with you that you have to worry about.
Ignition systems, injector systems, fans, adjustment motors, and a host of others all put out RFI, EMI, and AFI. If you're running FM, none of this is of too much worry. But there are a few things you might have to worry about.
Car stereo systems, no matter who made them, are a bane to any type of amateur operation. There are so many different problems, it's best to search here on this forum for ideas if this problem area arises. Remember this, even the high-priced name brands are susceptible to all matter of interference.