Hi, I am new to the forum, I live in Florida and have 2015 f150 V8 fuel flex . I been having an idling issue with my truck where I be at the light or stop and the truck start to idle bad, Rpm drop low and bounces and the truck shake all the sudden comes and goes that sometimes the idling gets so bad that the the truck turn off and I have to start it again . I notice it does happen more and worse with regular gas comparing to e85. I took it it a shop and they kept it over night to duplicate the issue and they said that my throttle body needed to be cleaned and calibrated and he did that but the problem still happening, he checked spark plugs and said they were fine and also no check engine or error code. We bought the truck 4 months ago from dealership and currently have around 120k miles. I decided to post it on here to get help from experts and see if I can figure it out my self with y’all help. Any help will be appreciated

 

My 2015 F150 XLT 5.0L V8 had that issue were every time I came to a stop it would ruff idle once or twice and when die. We ended up replacing the variable timing solenoids and that solved the problem for me.

 

Does the problem happen on a regular basis, or only at certain times, like when the truck is cold or hot, or right after you fill up the fuel tank?

 

Idle issues are sometimes caused by a bad Crankshaft Position Sensor.

 

Check vacuum hoses…

 

where is that located ? And was it hard to replace ?

 

regular basis doesn’t matter where or how hot or cold

 

the shop checked for vacuum leak and said everything is good

 

Variable cam timing is a common cause of poor idle when spark looks good on higher mileage vehicles. A competent tech can run a log and see if the solenoids and cams are operating out of spec or close to it. I'd check that before throwing parts at it.

 

I’ll check that and the part is not expensive, where is it located ?