Accelerating on its own, P0171 P0174 jumping tach meter, accelerates when steering turned
2001 Ford Windstar, 206K
Has always been a great car, but the last month or so, it has went crazy. It
accelerates on its own, jumps forward at lights & stop signs and I have to
keep brake pressed so it doesn't take off on me...It also is jumping from
500-1K on the tach and sounds like it is going to stall (when its not revving
up to 3K) so, I end up giving it some gas at times to keep from stalling and
holding brake at same time so it doesn't take off.
When I turn the steering wheel while setting idle, the car revs up to 2-2.5K.
I have replaced the spark plugs, Cleaned the EGR Valve, replaced the
throttle sensor, replaced the fuel filter, replaced the Idle control valve,
CLEANED the MAF, changed the air filter...still with no luck and scared to
keep spending money on a 2001 Windstar that is basically not worth much,
but I can't afford a new car, so I have almost no choice but keep nickeling
and diming me :( Any suggestions would be greatly appreciated. ( I have
also looked for Vacuum leaks, and cant seem to find any, but going to
recheck that and also read about replacing the PCV Valve hose) Anything
that I am possibly missing as to why my car accelerates on its own? I shift it
in gear and it literally takes off! Also I have a motor mount that needs to be
replaced also. And my brakes also keep going out...they just completely go!
Brake goes to the floor and ZERO brakes, I keep adding fluid, and it keeps
disappearing! Every 4-5 days, I have to add 1/2 bottle of brake fluid. Its not
leaking (I park on cement) and I have checked around all the tires, no
leaks.. I have read that fluid is possibly backing up in the brake booster? I'm
a single mom of 2 little ones that feels incredibly unsafe, but like I said, it's
my only means of transportation. Any help would be appreciated.
P0171 and P0174 are classic codes for a vacuum leak. Which means unmetered air after the MAF is being detected by the system. Check all your rubber hoses around the intake and PCV. You can spray some carb cleaner around those areas while the engine is running and if the idle goes up, there is your leak. Also a leaky gasket on the upper manifold can do the same thing. You can have your mechanic perform a "smoke test" to pinpoint the leak if you can't find it on your own.
Sounds like you have a bad brake booster check valve also a bad master cylinder.
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