2008, 1500 miles. Stock except for the Napa muffler ala BlueToad’s instructions on an old thread I found (much quieter). It’s a good size muffler, don’t think it’s a restriction and it didn’t run any different before. Also the original owner changed clutch weights, what with I don’t know. It runs like a top other than the cold idle. I thought it was normal until I bought another 08, and it’s smooth as silk.

Ok, so here’s what I’ve done.

Changed fuel pump. No change. Never have checked fuel pressure, but never cuts out at high rpm and always starts great hot or cold.

Spark plugs, no change. Ohm tested wires, both the same.

Cleaned tbap, also exchanged it with the other rzr. No change. Chased the wires to the ecm and ohm tested, all 4 perfect.

Set the tps to .732 volt at idle. Actually messed with this quite a bit. It was .665 to start with iirc. Set warm idle speed to 1090, +-10. This is as fast as I can go without kicking the belt in and getting a jump when going into gear. Actually wondering if this is an issue, not sure what’s going on there since the other one idles at 1230 or so.

Good battery, optima red, get 14 volts while running. Same voltage to the fuel pump as the other one, can’t remember now what exactly.

Swapped ecm with the other one, no change.

Checked voltage of tps all through throttle range, goes up smooth all the way to 3.7 or so, can’t remember the exact number.

I’m about out of ideas except to up the idle to 1250 range, let it cool and see what that does when cold. Then if that fixes it address whatever clutch changes I need to make. Or just go with it as is, it never dies, just sputters and starts off around 800 rpm for a bit then works it’s way up. It was fine this way even in the cold all last winter. It just irks me to not be able to figure it out!

Utah RZR Rentals