Hi Everyone just bought a 99 expedition and have a few questions

[bowman1268]

Hi everyone

I just bought a 1999 expedition because I had my 150 stolen and well Lets just say by the time they found it it wasn't worth having anymore.So I needed a car in a hurry and found my expedition on craigslist.So far I am liking it but have found a few things that either confuse me or have me concerned. The engine has a re-manufactured by ford tag on the bottom of it. I am fine with that but have concerns about how well it was installed.The engine is running a bit rough and the rpms bounce from 800 to about 950 in park. If I give it gas it stumbles a bit and seems down on power.I just ordered new plug wires and plugs since the ones on it are a big mishmash of several brands.I plan on cleaning the throttle body and egr today.Is there anything else I should look at that is common on these 4.6 engines that may cause this?Also I noticed on top of the fact the heater core has been bypassed that there are two sensors that are connected to nothing just behind the alternator.I have tried to attach a pic of them below.One last thing I have four wheel drive but the selector seems to do nothing When I turn it from awd to 4wd or 4low no indicator ever comes on on the dash.How should I go about trouble shooting this?Thanks for any and all help and suggestions you can give I have never owned a ford or a suv.All my cars have been small so I am feeling a bit out of my league.

 

[qcksnake]

on the 2 sensors one of them is a coolant temp sensor. On the 99s they use the CHT temp sensor. SOme of the F150 actually have both in the 96-00 trucks so i would assume you might as well. IF its running rough this could certainly be the cause. there should be on drivers side a 2 pin connector going to a wire that comes off harness and goes under the intake. That will be your CHT connector. take a look around and see if somewhere on the drivers side harness you see any connectors for the coolant temp sensor. If you cant find it i wouldnt sweat it much, just means your reman motor probably had different intake with it and the best way to stop the coolant holes is leave the sensors in there. I dont work on a lot of expeditions, just dont see as many of them as f150s, and out of those i work on even fewer 4.6s.

The other sensor is the IAT sensor, your 99 may possibly have it integrated with mass air meter so agian, here is where they simply left it to plug the hole. Or could be left it unplugged, just take a look for the connectors.

Different year models and different vehicles can be a pita on this stuff sometimes.
Hope that helps.

As for the 4wd, do a search around here. there are 2 solenoids ran by vacuum on the firewall beind battery and a vacuum canister on the front diff. There is also an electric motor that controls the transfer case under the vehicle. could be any of these causing the 4wd as well as relays behind dash.

 

[bowman1268]

Thanks for all the info I have a working temp gauge so I know something must be connected lol.I will snoop around and see if I can find where the connectors may be or see if I can find where someone might have cut them off.

 

[rburch]

Welcome!

 

[bowman1268]

Thought I would give a quick update.I cleaned the throttle body and egr tubes which were clogged completely shut.and while idle is smoother it still has a intermittent miss that seems to get worse under load.So tomorrow new plugs and wires go on.If that doesn't work what would you guys suggest I do next?

 

[onlyexilove]

I have a 98 with the 2V Romeo 4.6 setup. I know that the IAC tends to gum up a bit over time on these and more than likely you will find yours is also if you pull it. Most people reuse the IAC and sometimes forget to clean it. It is on the driver side of the intake. Takes 2 10mm or 8 mm bolts to pull it off and a single electrical connector with the rubber hose running over to the intake. I did the PI Head swap on mine and didn't swap the IAC and kept popping codes until I swapped mine. When I pulled it I wondered how it was still working. I believe that both of those are temp sensors. You will either have the metal tube for coolant on the back passenger corner or the front passenger corner of the intake on the coolant runner. There should be a harness that sits below the compressor that routes to those sensors (harness only has plugs for those 2 sensors along with a tie down piece to hook on the end of a bolt over by the idler pulley). The 2000-2001 setup I believe is a bit different and they changed it up again in 2003-2004.

 

[bowman1268]

Thanks for the heads up I will check and see if I can find the harness in the morning.I believe my coolant connection is on the back passenger side I never noticed it on the front while replacing the plug wires today.She is running much better.I cleaned the iac while I had the throttle body off so it's good to go.
I cleared the check engine light and it hasn't come back yet so we will see what happens with that.




Oh does anyone know what size the factory exhaust is I have a few exhaust clamps missing and I am terrible at eyeballing the size of those things.

 

[eastmonsoon]

Welcome!