why wont my 4.3 rev past 3000 rpm

Here's a long shot. It might not know that it's in gear. Modern engines can only rev to 3000-4000 in neutral or park so they don't blow up. I don't know how to check it or fix it but get the codes read to see if anything turns up.

Roy bean have you been hitting the bottle again. Egr and PCV won't prevent engine rpms from increasing. Its either as Tenspeed said, computer controlled rev limiter or a common one is a clogged exhaust, the most common under that category is backed into a curb and bent something or clogged cat. Inspect exhaust and if nothing looks bad then pull the front most O2 sensors and run it to look for improvements. Lack of air flow, and lack of fuel pressure are usually the cluprits.

Clogged cat or exhaust. Tps maybe but idk on a 4.3. Explain to me how the pcv system will stop the engine from reving. Open egr would cause bad idle, closed egr will run good no matter what.

Egr and PCV recirculate an unbelievably small amount of unburnt hydrocarbons and the only time it will affect anything is at an idle when it's stuck open. It will NOT limit an engine to 3000 rpm and it will NOT cause the computer to become confused for any reason. A clogged catalytic converter or clogged exhaust, usually from being bent will limit the engines rpm because it can't "exhale". Exhausts get bent on a daily basis by people backing into curbs and a 10 year old catalytic converter is right at the common fail age. A rev limiter thinking the car is in neutral or park is also a likely hood and it wouldn't be the first time it was what caused this issue for someone on this site. Being from lake county Indiana we had the same emissions as California and I'm telling you the issue isn't a PCV valve or and egr valve. Btw its a post 2000 GM so the egr is elecrltronic not vacuum operated, and his issue is the vehicle won't to past 3000 rpm, NOT it's decelerating funny. Read the issue before you pull an answer out of that hat.

Here's a good question,"Why would you want to rev your engine over 3000 rpm in park"?

Its an 03 the distributor is electronic not vacuum or centrifugal. GM went to electronic distributors in the late 80's

Since it's obd 2 issues with the ignition would trip the light.

Timing belt has jumped a tooth~

Gear driven not belt and it would run horribly at all times if this happened due to how small both gears are, it would put the valve timing about 30 degrees out~

2002 Chevy Venture Extended Mini Van, makes awful noise as it takes off. With engine noise, I can drive at 50MPH. Checked in neutral and engine is smooth but noisy. Maximum RPM is limited as speed drops, RPM just cycles. It sounds like exhaust is blocked. Exhaust system was replaced, but not catalytic converter. Could it be a melt down converter, and blocking exhaust? Will MAP indicate excessive exhaust back pressure? Need help!