The original problem was a rough idle/stall. I replaced the IAC with little to no effect and then found a massive vacuum leak at the PCV valve end of the hose (hard plastic tube is in between the two rubber ends). I removed and replaced the PCV valve and valve-side hose section and that helped but did not completely fix the rough idle, so I ignorantly adjusted the throttle stop screw so the car would run.
Zoom to this year. My daughter told me that the car had no heat (heater core was clogged again) and has a rough idle again, and it wants go all by itself when she is not pressing the gas! While looking under the hood for clues to this problem, I found the leak that I could not find last year on the other end of the PCV elbow hose at the intake manifold. After I removed and replace the entire hose assembly, the car starts and idles better than ever, but a bit high. So I adjusted the throttle stop screw to hopefully where it was before I messed with it. Doubtful I got it right, but I reset the ECM each time I adjusted to clear the learned settings just in case.
So then I tested to see if this was causing her acceleration issue, but it did not have any effect.
When in drive, I get up to speed and release the gas pedal but the rpm's do not decrease. Car eventually slows down, but only after quite a while. I can travel miles at forty five mph without touching the gas. This is true if I use the cruise control or not. If I apply the brakes, it will slow down, but it is like the gas pedal is still being pressed down. When I place the transmission in neutral, the rpms go up. This only happens when in gear. When I come to a stop, I have to brake until it shifts to first gear, then it settles down to a manageable rpm. It idles at 750 rpms at a stop. But once I take my foot off the brake, rpms will slowly climb up to 1500 rpms shifting into the next gears. I also noticed that while accelerating up to fifty five to sixty mph, there is sometimes a "rough" spot around forty five to fifty mph where the car sometimes loses power or shudders very briefly and feels like I ran out of gas or is trying to shift gears, but then just as quickly, it recovers. I also must add that whenever the climate control switch is placed in any position clockwise of the center off position (floor and dash, floor, WinDefr and floor, WinDefr, respectively), or in the two AC settings, the rpms spike up to 1500 rpms and the AC clutch engages. This does not happen when using the dash vent position. I thought that the clutch should only engage when set to AC/MAX AC or the two defrost positions, but maybe that is how Ford does it. In any case, the spike in rpm cause the vehicle to suddenly lurch if in any forward or reverse gears. There are no codes being thrown by the computer.
What I have tried:
I have tried pulling up on the pedal from under it to see if the pedal is sticking, but no effect. I have inspected the throttle and cruise control cables/linkage, and there is no issue there. I have sprayed a whole can of starting fluid all over the vacuum hoses and fittings and have not found a single change in rpm. I have cleaned the throttle body no effect. The car did not have a "check engine light" for the TPS, but I replaced it anyway -no effect. Removed and replaced the Idle air control (again), no effect.
Any advice would be appreciated!
have the same problem?
Wednesday, January 4th, 2017 AT 8:10 PM