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Hello there i have a 2002 jeep grand Cherokee i just put a new intake and exhaust gasket install and all 4 02 sensor put in it put it all back together and pulled all the wiring harness in but when u start it the rpm increases and have to shut it off before it gets to high it back fires after it gets to about 2500 Rmp idk What to say about it could it be a bad gadget i installed
Thanks HUchters358
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Hi Guys. I am his father and like he said we just replaced all 4 O2 sensors. As doing this I replaced the intake and exhaust gaskets while I had it all apart.. As we put it back together went smoothly. Everything just fit right back together. So then we started the jeep and we got 4000 plus rpm and higher as we just shut the jeep off. We did get an engine code of PO505 which is IAC Malfuction. took it apart and cleaned it and still have the same problem. High High idle. So we are completely confused what the problem is.
Thanks
Hutch74Does it stop increasing at a point or will it continue until it hits the Rev limiter? Make sure you connected everything and check the vacuum lines specifically.
That is the exact symptom of a manifold gasket leak, I fought with one a few times. Loosen all the manifold bolts and try again, you can probably reuse the gasket but torque the 3 exhaust bolts first. Leave the bottom bolts in just a couple threads to slide the intake manifold on, then tighten the bottom bolts first and the top ones last. You can try flipping the manifold gasket around, or depending on how hard it was torqued you might need to buy another one.
yes all the vacuum are all connect i think it is the gasket like stiv625 said
will try to flip it and what are the toque specks for the gasket for the 2002 jeep grand cherokee 4.0L
Thanks Huchters358
Something like 25-30 ft lbs. I went tighter than that though. I think the order is more important, torque the two bolts in the middle on the bottom first and work out from there. Make sure the intake manifold is lined up perfectly with the locator dowels before torqueing down. Good luck.
So we have taken it all apart again and restarted like previous post. Still having the same issue with high rmp so we just turn the jeep off before it does anymore damage. Gonna order a new gasket and see if that makes a difference. Is there anything else it could be. O2 sensors???
Thanks
Hutch74Thinking about it know. We did replace the injectors about 8 months ago. Maybe could be getting to much fuel as they are not stock injectors. Put in 2004 ford mustang injectors in it. Not sure thou just throwing things out there.
Hutch74
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