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When I got the truck last fall it was really bad and the idle was surging all the time. The PO had changed the IAC but that didn't do anything. Since then I have changed all vacuum lines except brake booster vacuum hose which seems fairly new and the hose going to the vent actuator (not sure what the correct name is).
Do not forget the vacuum reservoir on the passenger side inner fender. There is another small vacuum reservoir for the HVAC system on the side of the blower/heater/evap case that has been to know to crack. If the truck has factory Speed Control check the vacuum reservoir behind the driver side headlight.
Originally Posted by minimalist
The TPS is adjusted correctly
The term "bad TPS" meant it may have a bad spot in it. At closed throttle it may output correct, but when applying throttle the output may vary because of a worn/bad spot. You can try to monitor the TPS output with a DVM to watch for dips/peaks when moving the throttle (Key On Engine Off). Best tool to do this is an oscilloscope, but very few have one or know how to use it. An old analog volt/ohm meter is another tool many suggest to use as well.
Originally Posted by minimalist
I never checked the shaft on the throttle body though. Will do that hopefully next weekend.
Great idea.
Originally Posted by minimalist
If I have time I will also take out the PCM to look at it.
Another wise choice. If nothing else consider it preventative maintenance given the increasing frequency of leaking capacitors.
Thank you for your suggestions. It will take a few weeks till I am through with all this. Very busy at work and wife wants some new paint on the walls. At least I have some say in the color.
And did another smoke test over the weekend. This time I used a compressor driven machine instead of a bicycle pump or cigar and it was a huge difference and eye opener. I should have gotten one of these machines a few month ago. Long story short I fixed another vacuum leak.
I also had smoke coming out at the fuel vapor cannister/charcoal container at the nipples on top. Does that mean the cannister needs to be replaced?
Computer is looking good I think. Here are some pictures.
This Hennessey Takes the Expedition Tremor's Off-Roading Capability to the Next Level
Slideshow: The VelociRaptor Expedition gains a lift, upgraded suspension, Brembo brakes, and trail-ready equipment while retaining the stock 440-horsepower EcoBoost V6.
Rezvani's Latest Post-Apocalyptic Monster Is a Ford F-150 Raptor Underneath
Slideshow: Called the Fortress, the 850-horsepower pickup combines Raptor underpinnings with military-inspired features, survival equipment, and a starting price of $285,000.
