Ok, so did the intake upgrade on my 97 XJ Country. The first day, everything was good. Second day, the drive to work was good, but on the way back on the interstate it blew off my muffler and the jeep felt like it was going to shake apart. I have a magnaflow cat and stock muffler. I'm thinking that it just tried to send too much air through the muffler, but the shaking to death has me worried. Once I got home, I let it set for a bit and it started up fine, but once I got it into my garage and worked with the muffler cat connections, then when I tried to start it up, it wouldn't turn over unless I put the gas petal down. Then it would rev hight for a second then drop to around 1k. So needless to say I need so help.

 

I'm thinking slight leak in intake or not lined up 100%.

 

I have everything torqued down and lined up.

 

What are the codes?

 

I don't have a code reader and no check engine lights are on.

 

Ok barrowed a code reader, and the only thing it's reading is a heat sensor malfunction.

 

WTF is that?

What P code?

 

It the sensor that connects to the thermostat

 

Sounds like the Engine Coolant Temperature Sensor. It will cause engine performance problems but I don't know if it will nuke the engine like you describe.

Try changing it and see what happens.

 

I also changed the motor mounts out to the Daystar poly. I think I might not have then tight enough.