Terrible surging and stalling
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Senior User
Joined: Jun 2009
Posts: 207
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From: Oklahoma
Terrible surging and stalling
Hi All, I come here often to read so I just joined today as I could use some help with a problem I am having with my 1985 F150 302 2bbl pickup. Here it is, engine surges from 500 rpm to 1500 rpm then back down constantly, sometimes will die when turning a corner as you remove you foot from the gas pedal. Carb seems very rich also. What I have done, new plugs, new wires,new air filter, changed oil & filter all of which it needed anyway. Sometimes when I start it it will run fine for a bit then start surging and missing. I only drive it about 200 miles a year but I keep it in good condition, until now, any help appreciated.
thanks okiepc1
thanks okiepc1
FTE Legend
Joined: May 2008
Posts: 56,542
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From: In my own world
sounds like a vaccume leak. spray carb cleaner at carb, and intake while truck idles. listen for raise in rpm, you found your leak. vaccume lines could be cracked, broken, missing. carb could be loose. if you don't find a vaccume leak, check your codes before you spend anymore money. no sence in spending money/time unless you need to
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Joined: Jan 2001
Posts: 57,005
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From: Virginia
I agree, it sounds like a vacuum leak. If you cannot find any hoses cracked or off their connections, I would then look at the carb. The fuel they have now has lots of ethanol in it, and it is very hard on the carb and the carb rubber parts inside. And sitting around a lot doesn't help, as the fuel goes bad very easily, clogging the carb up. If the vacuum lines check out, I would rebuild the carb.
Thread Starter
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Senior User
Joined: Jun 2009
Posts: 207
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From: Oklahoma
Thanks for the replies, I checked for vacume leaks, could not find any, still surges. A person asked if I had tried a new throttle position sensor, claimed it causes this effect?
What do you think before I plop down $50 for one?
thanks
okiepc1
What do you think before I plop down $50 for one?
thanks
okiepc1
Thread Starter
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Senior User
Joined: Jun 2009
Posts: 207
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From: Oklahoma
OK, all is good now, turned out to be the power valve was shot, draining the bowl & dumping fuel into the intake. After repair I changed oil & filter just in case. Runs like new as it has only 72K miles & I am second owner for 10 years now, had only 49K when I bought it.
Thanks for the input, I will post a pic soon
okiepc1
Thanks for the input, I will post a pic soon
okiepc1
