Engine won't run without throttle

ncyrider · May 13, 2015

Have a 2001 ST with around 80k miles, it's had this problem many times before, where out of nowhere the engine will not stay running unless I keep my foot on the gas pedal. It has always fixed itself within several miles of driving, but the problem is back now and this time it won't go away. Drove at least 20 miles on the freeway and it hasn't gotten any better. Recently dumped a bottle of Lucas Oil fuel injector cleaner in it too, and I know that's not the solution. So what's causing this problem? If there's any parts I need, I will order them asap.

Also, I have heard stuff about a PCV valve fix on these trucks and something about "job 1/job 2". What do these fixes do, and where can I order the parts from?

swshawaii · May 13, 2015

Sticky: P0171 & P0174 4.0L SOHC's Sport/Sport Trac

http://www.explorerforum.com/forums/showthread.php?t=314670

ncyrider · May 14, 2015

I actually cannot locate the pcv hose/elbows with the 90° angles on my 2001. The pictures I'm seeing in this thread look somewhat different from my engine. There is a sticker on the engine that says it was made on 5/10/2000 if it makes any difference, and the layout of things under the hood is different from other 4.0's I've seen. A ford dealer has the pcv hose assembly (motorcraft kcv-190) in stock and I need to fix this thing now...should I buy it or is there a different part I need?

gtyates · May 14, 2015

No check engine light? I would say it is the idle air control valve (IAC).

swshawaii · May 15, 2015

Good call on the IAC, although OP has classic symptoms of failed intake gaskets on early SOHC's. It's a Job 1 engine.

http://www.explorerforum.com/forums/showthread.php?p=3419190

ncyrider · May 18, 2015

I haven't seen the check engine light come on in this truck in years. After a few days of dealing with this problem, it finally fixed itself again, like it always has. I know this problem will most likely come back again so I still want to fix it right away. With the IAC, how can I check if that was causing the problem?

swshawaii · May 18, 2015

You can't because a dirty IAC valve seldom throws a CEL or trouble codes. Should be considered preventative maintenance. TB also.

http://www.mysporttrac.com/mysporttrac/projects/CleaningIAC/CLEANING_IAC_MOTOR.htm

http://www.mysporttrac.com/MySportTrac/projects/ThrottleBodyCleaning/Throttle_Cleaning.htm

Kjhadfield · May 18, 2015

swshawaii said:
You can't because a dirty IAC valve seldom throws a CEL or trouble codes. Should be considered preventative maintenance. TB also.

http://www.mysporttrac.com/mysporttrac/projects/CleaningIAC/CLEANING_IAC_MOTOR.htm

http://www.mysporttrac.com/MySportTrac/projects/ThrottleBodyCleaning/Throttle_Cleaning.htm

When I did mines last yr, I couldn't believe how gunked up it was-I had a rough idle issue which fixed that. I also cleaned the maf and drop in k&n while I was going down the line-might as well. I'd be curious to look at mine after a year to see its current condition. I didn't know this then but checking to make sure your throttle cable/pedal fully opens-I guess it can lose tension at the firewall?

ncyrider · May 19, 2015

So I should replace the IAC valve, even if it's not causing the problem? It's never been done on my 2001.
Is this what I should get? > http://www.amazon.com/dp/B000EQA4BK...TF8&colid=3R6S14MWXAM0J&coliid=I1488S8HBP76P4

What else should I think about buying? I want to do ALL the preventative maintenance and "job 1 upgrades" or anything else recommended (engine wise) because from what I know, none of this has ever been done on my truck. But I have cleaned the MAF sensor and keep the K&N filter clean.

swshawaii · May 19, 2015

Try CLEANING the IAC and throttle body first before changing parts. Do one at a time and test. Use both links in post #7 .

Engine won't run without throttle

ncyrider

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swshawaii

ncyrider

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gtyates

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swshawaii

ncyrider

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swshawaii

Kjhadfield

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ncyrider

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swshawaii

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