1987XJ4.0i6

I'm spitting straight black smoke like a diesel. I've even been asked if it was. Its not, its the 4.0 i6. The PO replaced the map sensor, throttle position sensor, throttle body and sadly and idiotically removed the stock exhaust, muffler and cat, straight piped it with a thrush flowmaster exhaust. I get terrible gas mileage and I'm wasting fuel something I'd never want to do, just throwing money away. I can smell raw gas and she runs like a stuffed pig (super rich). I'm asking foe causes, tests and fixes. Constructive criticism, anything that helps really. Thanks from a fellow xj lover.

salad

He replaced the MAP huh. Go take a look at it, it's probably unplugge or the little vacuum tube is gone/broken.

Rogue4x4

Replace the missing components in the exhaust as well. O2 sensors have an effect on your mileage. Plus it isn't legal. Especially if it is street driven, whether you have inspections where you live or not.

1987XJ4.0i6

Alright I will after class, one of the vacuum lines for the cruise control is cut, could this cause any problems with how the engine runs?

1987XJ4.0i6

Turns out I got another map sensor from the jy, so the plug and tube are in there pretty good, I'll check the other sides of them today though.

salad

Yes. The MAP sensor controls fuel mix based on vacuum.

Roninofako's also spot on.

1987XJ4.0i6

Yeah, I most definitely want to replace the cat when I have the money to do so, I will go to the jy soon and look for a new line for the cruise control.

cruiser54

Check this stuff.

WarPath

Make sure how before you fix it you dustcrop some priuses

1987XJ4.0i6

Hahaha