Need the Vacuum Diagram for a 1988 Jeep Wrangler 4.2 liter

isc filthy and sticking open
or TPS bad.
the 2 top fails for out of control idle on 4 liter.
or vacuum leaks

Check HERE for few engine sizes:
- 1999 JEEP WRANGLER - L4 2.5L 150ci GAS FI N P
- 1999 JEEP WRANGLER - L6 4.0L 242ci GAS FI N S

Hope this help (remember comment and rated this post).

Thank you for taking the time to respond.

Visit autozone.com (free register); in there you can find the repoair guide about Jeep Wrangler and more details, like VacuumDiagrams...



Fig. 1: Emission control vacuum schematic-1987-90 with 4.2L engine and automatic transmission



Fig. 2: Emission control vacuum schematic-1987-90 with 4.2L engine and manual transmission

I hope help you with this. Good luck (remember rated this help).

The powdery black substance tells me that your egr valve is not working.And that is operated by the vacum sysem.The pipe has probebly come of the EGR valve.

Go to your local library to find this book.

check the following link
"http://www.ebooksquad.com/2008/02/21/1988-jeep-cherokee-wiring-diagram-symbol.html"

here is a link with all the vacum diagrams for your jeep. hope it helps.
http://www.autozone.com/addVehicleId,1076002/initialAction,repairGuide/shopping/repairGuide.htm?pageId=0900c1528008ab9d

you could have vacumm problems making it seem like the timing is off, but the other guys are right on the timing!!!! it could be throw-body problems, like crack manifold problems. This year has thhis type of problem sometime. Try spraying WD-40 around the vacuum hoses, & manifold to see if the motor changes rpm????