Should be able to tell from either the VIN or the RPO code sticker if it's a real z34 or not. It's certainly more likely it's add ons to an LS. But it's also possible the 3.4 blew and they dropped a 3100 in since it's so much cheaper.

Good points, bumpin.

(By the way, the RPO code sticker will be on the underside of the spare tire cover in the trunk.) ;)

Yes, the VIN will tell for sure which it really is.
2G1WW will be an LS (eighth digit will be 3100's engine code M);
2G1WX will be a Z34 (eighth digit X (or K for '98-'99 3800 engine).

I strongly doubt that there was ever any mixing around with trims and engines; in other words, no LS with the DOHC 3.4, nor any Z34 with the 3100. Chevy kept it simple; it was either one or the other.

^x2 on RPO. All z34s 90-97 were 3.4 dohc. So if z34 the codes on RPO tag on trunk lid will have at least these two rpos-lq1(3.4 dohc) and f41(HD suspension)

Car Sputtering
 

Hello need some help on the issue i am having with my 96 monte carlo
I have hooked it up to a computer and no codes are firing. MY problem is that when i hit 40 mph the car sputters and jerks until i hit 60. Was needing some Ideas on what the issue could be before i start just replacing a bunch of parts.

2 ideas
 

2 things to check are the Fuel Filter should be under the Passenger seat outside the Car looks like a small beer can with tube fittings both ends.
Should be replaced every 30K.

2nd thing would be the Catalytic Converter maybe full of the junk and may need to be replaced, this is the only option. It will bog the engine for sure.


Make sure the exhaust system is not plugged.
Also check and replace the Air filter, the car needs to breath.:confused:

^Agreed. Might as well check spark plugs, wires, and fluids while you're at it.