Summers22

iTrader: (2)

LOL, its all good. I had a 5.4 2V, and yes, they have an IAC.

Summers22

iTrader: (2)

I am not sure, I know there are several threads that clogged cats caused idle issues.

You should also seriously consider replacing the upstream O2 sensors on each side. Just replace the upstream, the downstream really only monitor and do not "adjust" air/fuel ratios. Now, I know every truck is different, so the following tune-up acvice may not work as well for you. I bought my truck with 113K. I replaced all 8 spark plugs with Motorcraft Sp515, all 8 COP's with Motorcraft, fuel filter, both upstream O2 sensors, cleaned my MAF, removed and cleaned my throttle body, did the Gotts mod with a AEM dryflow air filter. I run an Edge Evolution converted to a Gryphon. I also changed out my transmission fluid and filter. Drained and filled my rear diff with Mobile 1 fluid and Motorcraft XL3 friction modifier. My truck now has 126K on it and runs PERFECT in every aspect.

powerranger262

I have heard that after a drive, you can take a look at your cats, and if they are stuffed up, they will be glowing red. Besides that, a good, trusted exhaust shop should have some tricks to tell you for sure.

Especial86

iTrader: (1)

I'd take a look for a Vacuum leak somewhere.. On the driverside of the intake manifold there is 1 vac hose prone to rotting. It's fuel evap hose.. Check there and around the motor with the truck running to see if any wiggling or jiggling of the hoses improves the idle at all..

If a fresh battery reset (disconnect) fixes the problem for a little while, but then it steadily comes back, I would consider replacing the throttle body or changing the TPS...

If you have a tuner you can also raise the idle which is set pretty low IMHO from the factory on some models..

1 last suggestion would be an induction cleaning with seafoam to help get rid of carbon buildup and help clean up the CMCV runner plates in the intake manifold...

Summers22

iTrader: (2)

I agree with Especial86 on the seafoam. I had a code for IMRC (intake manifold runner control) stuck open, cleared it twice and it came back. After using seafoam in my brake booster line, the code went away. That was 20K ago....

Was the throttle body removed when you cleaned it, or was it on the truck when you cleaned it? Big difference in the two.

Snoopaloop

I took my throttle body completely off. The top side of the plate looked fine, but the bottom, the side facing the engine, was dirty. A can of crc throttle body cleaner took care of that though.

Summers22

iTrader: (2)

Cool, thats what needed to be done. Also, you need to change your O2 sensors. If they have 136K on them, they are not working properly. As stated, just change the 2 upstream sensors closest to the exhaust manifolds.

Snoopaloop

Ok, thanks a lot. By any chance, would you have a recommendation on which ones I should get? I was thinkimg I should stick to motorcraft, but I could be mistaken. Are the upstream O2 sensors any different than the downstream ones? How hard are they to replace? Thanks again

Summers22

iTrader: (2)

Stick with Motorcraft, that is the only replacement brand I will ever suggest. I dont know if there is any difference. Only the upstream send adjustments to the PCM, the downstream "monitor" but do not adjust anything. The passenger side connector is a bit of a pain, be ready for some knicks and cuts on your hands....lol

I got mine here, you need 2 of course, it works for either side.

http://www.ebay.com/itm/Motorcraft-DY-835-Oxygen-Sensor-XL3Z-9F472-AA-/181497471225?pt=Motors_Car_Truck_Parts_Accessories&hash=item2a4217a0f9&vxp=mtr

Summers22

iTrader: (2)

^^^Those are about $ cheaper each than Rockauto, plus you still have shipping over there. So these work out to about $20 cheaper for the pair.