Yet another IAC question
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Junior User
Joined: Aug 2003
Posts: 95
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Yet another IAC question
I have taken my IAC valve off to clean it and I was reading some posts that said that there should be something in the IAC that should move freely. When I look at my IAC I don't see anything that moves, just two holes and a spiral shaft inside. It is totally black inside which I assume is from carbon buildup. Does this mean that the moving part is totally stuck? It is a 91 F-250 351 with 109K. Trying to solve a miss at idle and slight hesitation on acceleration. Replaced all maintenance items plus ECT and 02 sensor. Any thoughts?
Cross-Country
Joined: Jul 2004
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Tune Up
That really sounds like a very dirty Intake Air Control. The black (probably carbon) sounds odd, especially for 109 K.
Take apart the intake sustem. Clean everything with Fuel injection cleaner.
Replace the air filter
Replace the spark plugs
Replace the plug wires (Do this especially if they are over 50 K old or you are not sure. Besides it sounds as though you have one or more misfiring cylinders)
Replace cap, rotor, check coil
Check the Engine Coolant Temperture sensor and be absolutely sure you use the correct one.
Run the codes, since this will tell what is wrong for sure.
Take apart the intake sustem. Clean everything with Fuel injection cleaner.
Replace the air filter
Replace the spark plugs
Replace the plug wires (Do this especially if they are over 50 K old or you are not sure. Besides it sounds as though you have one or more misfiring cylinders)
Replace cap, rotor, check coil
Check the Engine Coolant Temperture sensor and be absolutely sure you use the correct one.
Run the codes, since this will tell what is wrong for sure.
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Junior User
Joined: Aug 2003
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lorenr,
On my own I have replaced the spark plugs, wires, cap, rotor, air filter, fuel filter, PCV and ECT. Put seafoam in tank and brake booster hose. Checked for vacuum leaks (kinda) and sprayed TB plates with cleaner and cleaned EGR.
Took it to mechanic and he hooked it up to machine and found there was a bad coil, thermostat was faulty. He replaced coil, thermostat, O2 sensor.
He said he thinks it might be injectors but told me it wasn't worth it to fix.
When I intially pulled codes the only significant code was 337 which is EGR related and was told it could be caused by a number of things.
I was thinking I might just try replacing the IAC valve since it is original and prone to failure. Any thoughts before I dump more money into it.
On my own I have replaced the spark plugs, wires, cap, rotor, air filter, fuel filter, PCV and ECT. Put seafoam in tank and brake booster hose. Checked for vacuum leaks (kinda) and sprayed TB plates with cleaner and cleaned EGR.
Took it to mechanic and he hooked it up to machine and found there was a bad coil, thermostat was faulty. He replaced coil, thermostat, O2 sensor.
He said he thinks it might be injectors but told me it wasn't worth it to fix.
When I intially pulled codes the only significant code was 337 which is EGR related and was told it could be caused by a number of things.
I was thinking I might just try replacing the IAC valve since it is original and prone to failure. Any thoughts before I dump more money into it.
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Junior User
Joined: Aug 2003
Posts: 95
Likes: 1
I think I have decided to pay the 76 bucks to have this mechanic up the street take a look at it to see what the real problem is. I am starting to think it is a fuel injector problem. Before I bought the truck it has sat for a long time and think some gunk has clogged an injector. I hate to spend another 70 bucks on a part that isn't the problem. I'll let you know what I find out. Thanks for all the help.
