Vortec 3500 I-5 engine - Good or Bad?

About the only problem we have seen so far is a misfire problem that can be traced back to exhaust valve springs. This is a rare condition, and I imagine the vehicles you would buy right now have already been updated.

Ian

I bought an 04 about 3 months ago. Decent power until you put a trailer behind it. Mine is a 3.73 rear end with traction control.

The I-5 is a good engine but 3.73 gears with 31 inch tires is too tall for I-5 to tow with. You want 4.10?s in it if you plan to tow anything with it at all and even then I would say 3500lbs or so tops.

I've had a Colorado for about 36K miles now, and am very happy with the engine. The only mild complaint I have (not really engine related) is that the cruise control sucks on hills - goes into passing gear too often. Very happy with it overall.

-= Larry A.

It is also the ZQ8 sport model with the 235/50ZR17's.