99 Expedition running rough
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Junior User
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From: Chicago, Illinois
99 Expedition running rough
So today I sprayed the throttle body of my 1999 Expedition with 205K miles with air intake cleaner as I usually do every couple of Months. I also sprayed some starting fluid in the the intake. I started the vehicle & it was a bit difficult to start *** is the case after spraying stuff into the intake, but after letting it run for a fee minutes, the idle was going up & down & the engine seems to be running on 7 cylinders. Is there a possibility that I fouled a plug? I had all of the coil packs replaced last year. Could one of the coil packs have gone bad? I double checked to make sure that all of the vacuum hoses were connected & they are.
Thanks in advance for any help!
Thanks in advance for any help!
Fleet Owner
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Which engine?
If the idle is going up and down then maybe you either knocked off a vacuum hose when you were in there, or dislodged something with the cleaner that is now making the IAC valve act sticky. I'd start by checking the hoses, then taking off the IAC and giving it a good cleaning.
If the idle is going up and down then maybe you either knocked off a vacuum hose when you were in there, or dislodged something with the cleaner that is now making the IAC valve act sticky. I'd start by checking the hoses, then taking off the IAC and giving it a good cleaning.
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I've got the 5.4L V-8. I'll double check the vacuum hoses & the IAC, which I'm pretty sure I replaced a couple of years ago. I would be surprised if the spray jarred something loose because I spray my intake every coupe of Months & 2 years ago I removed & cleaned it. It sure sounds like its running on 7.
Cross-Country
Joined: Oct 2008
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how long since you changed spark plugs? I replaced mine last night in a 98 expedition 4.6L. It had only been less than 2 years and maybe 30000 miles since they were last changed, made a tremendous difference in the way mine ran.
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How in the world do you get to the bottom bolt on the IAC? This thing is impossible to get off. I have taken the throttle body off before but I an trying to avoid doing so.
Any suggestions???
Any suggestions???
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Junior User
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From: Chicago, Illinois
Ok. I found one of the boots on a vacuum hose near the back of the intake was bad so I replaced the entire PVC hose cluster. Also replaced the two O2 sensors & PVC valve. The truck still idles badly, like it is running on 7. Should I replace the IAC? Also, could the MAF be bad? I sprayed & cleaned it but it does have 203k miles on it. If the MAF is bad would the truck run rough?
Thanks,
Thanks,
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Proccess of elimination my friend.
It was not running rough before you sprayed the TB. Re-trace all your steps and check everything you changed or removed to spray the TB.
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I recently sprayed/cleaned the TB on my Expedition. However, I had my wife start the truck for me and I feathered the throttle to keep it running so I could spray/clean it while it was running. This helps remove/burn deposits all through the intake track. I had no problems with my rig after the spray-down. the inside of my TB was NASTY before I sprayed it, afterwards it was nice and CLEAN.
Good luck!
It was not running rough before you sprayed the TB. Re-trace all your steps and check everything you changed or removed to spray the TB.
.
I recently sprayed/cleaned the TB on my Expedition. However, I had my wife start the truck for me and I feathered the throttle to keep it running so I could spray/clean it while it was running. This helps remove/burn deposits all through the intake track. I had no problems with my rig after the spray-down. the inside of my TB was NASTY before I sprayed it, afterwards it was nice and CLEAN.
Good luck!
Fleet Owner
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The easiest way to do this is to one at a time disconnect the 2-wire plug going to each COP. Once you disconnect one that doesn't affect how the engine idles, you've found the problematic cylinder.
Just so you know, each time you disconnect a COP, a code will be set and the CEL will turn on. Once you reconnect it and turn the key off/on the code should go away and the CEL go off.
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