How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Chris (aka- Moose) Your Own Question
Chris (aka- Moose)
Chris (aka- Moose), Technician
Category: Ford
Satisfied Customers: 47982
Experience:  16 years experience
Type Your Ford Question Here...
Chris (aka- Moose) is online now
A new question is answered every 9 seconds

Ford Excursion: Good Morning Moose- I have a 2005 ford excursion

Customer Question

Good Morning Moose- I have a 2005 ford excursion 5.4l v8.
I'm experiencing engine rev/flare at around 30-40 mph and sometimes at 60 mph. It seems to happen quiet a bit when it is hot outside (Texas summer) and seems to get worse when the AC is on. I'll be driving down the road under light acceleration and the RPMs will surge out of no where and now just recently the temp gauge bounces up and down from mid temp to Cold during the time the engine is flaring. Please help!
Parts that I've thrown at the problem :( are as follows: DPFE sensor, IAC sensor, TPS sensor, cleaned entire throttle body, alternator, fuel pump, all spark plugs and coil packs. note: when the problem originally started I had P0171, P0174 and p0450 codes after changing the SP and Coil Packs, fuel pump the codes went away. I'm not getting any CEL just the aforementioned problem. Your assistance is greatly appreciated!!
Submitted: 2 years ago.
Category: Ford
Expert:  Chris (aka- Moose) replied 2 years ago.
When it does rev up, does the vehicle speed increase? if not then we are looking at a possible transmission slippage issue going on here. How long and how high is this surge, increase in rpms? How does the trans oil look, smell, color, and level? You want a excellent 5 star answer & I would like to be rated the same for providing it. Consider I don't know your skill level & I can't see, smell, hear, or touch the vehicle. It may take a few back and forth replies. Try your best to respond with good detail so I can do the same. I normally log in at 3pm and work late. A rating is required. Your rating me, what I type. I am not an employee of this website, nor have control over the fees or the time it took to get a response. If you rate negative or not at all you still paid, but I get nothing. I want you pleased with me and my efforts, so let me know if your experience here has come up short.Thanks Chris
Customer: replied 2 years ago.
It's not a transmission ....I can unplug the connection to the Brand new ford OEM TPS sensor and it idles fine and drives without any engine flare or RPM surge and shifts fine .....It's like something is causing the TPS sensor to idle up and down when it is connected
Expert:  Chris (aka- Moose) replied 2 years ago.
Being its a cable driven throttle body, that rules out the throttle opening and causing this, but since the TP disabled resolves this that means the computer is seeing the throttle was increased so its changing the air fuel ratio to compensate by adding more fuel. I suspected a faulty TP or dirty MAF sensor or fuel pressure not steady.
Customer: replied 2 years ago.
Well we know it's not the TP ...I have a brand new filter and fuel pump installed by Ford 3 weeks ago ....I cleaned the MAF sensor ....I just don't want to keep throwing parts at a problem w/o some solid diagnostics. Hence, why I'm conversing with you :)
Expert:  Chris (aka- Moose) replied 2 years ago.
To complete that solid diagnostics, we need a a diagnostic tool, do you have one?