My 2000 has the 4.0. I always thought that it was a V6 before I bought it! But in doing some looking at it, it really seems to be a straight 6. Now I'm not a great mechanic. I never could tell the difference between a 302 and a 351 just by glancing at it like some people I've known. I was just looking at something on RockAuto and the only engine listed for my truck is a 4.0 V6! Is a 4.0 I6 the SOHC while the 4.0 V6 being the DOHC that's in Mustang's or other cars? And why wouldn't an auto parts company, even an online retailer like RockAuto know there are 2 different engines by the same name? I know AutoZone never asked if it was a V or I 6!

Yes before it all fell out, I was a natural blonde!

 

if you know what plug wires are you can count them. If they’re all on one side most likely you have a six-cylinder or four-cylinder. If there’s three on one side and three on the other side, you have a V6

 

The only way your 2000 Ranger could have a straight 6 (aka an INLINE 6), would be if an extraordinarily expensive customization was performed.
Are you the original owner? <<That's a mild joke.

 

The 2000 Ranger 4.0 6 cyl engine was V6 pushrod engine. The only inline engine that was offered was a 4 cyl. The 4.0 SOHC engine was not offered in the Ranger until 2001 and was also a V6.