94 Jeep Grand wont go over 3,500 rpms

[AndyHansen]

I have a 94 jeep Grand cherokee runs and drives fine it just wont go over 3,500 rpms if i put it in park and try to make it go over 3,500 it gets all wierd and wants to die. It has new distributor, distibutor cap,rotor spark plugs,plug wires,speed sensor what else could it be? you think the ECU?

[msdz]

It might be the rev limiter. Not sure exactly if it is built in the ECU or not but in park mine will not rev to high cause of the limiter. The limiter keeps the engine from revving to hard without any strain on it so it does not blow. Most vehicles have them nowadays. Older vehicles did not and you could hold them to the floor and blow the engine.
Might be able to find an aftermarket chip or ECU that does not have a limiter built in so you can rev it up higher if there is a need for it. I don't see why you would need to though unless you are neutral dropping it to get it to spin tires?!?!

[LeeRod617]

Originally Posted by msdz

I don't see why you would need to though unless you are neutral dropping it to get it to spin tires?!?!

On an automatic..not smart.. lol you're right.. no real need..if it drives fine.

[fredjacksonsan]

If it won't go over 3500 rpm, I'd suspect that the exhaust is getting clogged. On some Dodge trucks for that model year, the catalytic converter started to fall apart (do you hear a rattle in the exhaust?) and get clogged.

While the vehicle is running, have someone hit the gas while you're holding pressure on the tailpipe outlet. You should feel a strong surge of pressure; if not I'd suspect the cat.

Is it a 5.2 by chance? Also you didn't say how many miles.

[AndyHansen]

No its not only in park when im driveing, When it get to 3,500 it starts sputtering.Its not the exahust has new exahust 6" lift 33" swampers lots of new parts can the ECU be bad I can't think of anything else
4.0 inline 6

[fredjacksonsan]

OK you've got a new exhaust; did you replace the catalytic converters also? That's where you'll find the restriction.

A dirty air filter and state of tune can also contribute.