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Probe Member
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106 Posts
Discussion Starter #1
I've racked my brain, and I'm at a loss. I have this weird dip in my idle every so often. It was fluctuating really badly from 750 rpms down to 400 or so. So, I did the following: adjusted the timing, adjusted the idle screw on the TB (but I didn't ground the 1 pin black connector because I don't know where it is) i think it made some difference, then I replaced the cap and rotor, check the black tube for cracks and didn't find any, cleaned out the PCV system, ran fuel injector cleaner, replaced the plugs and wires, the O2 sensor was replaced when I put headers on last year. I notice the problem especially after I've been driving a while in stop and go traffic, when I have a bunch of stuff sucking power. When I come to a stop at a light and put the brakes on, put the clutch in, the car almost dies, but then the rpms shoot right back up.
I'm also getting a drop in power immediately after I shift gears when I'm gassing it hard. If I floor it, shift into second, there's hardly any power until 3500-4000 rpms. It still punches and you can feel the torque, but then it dies :(

So, any ideas? I think I've done everything possible :bwhoa1:
I hope it's not the alternator...that's expensive.
 

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Probe GT
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47 Posts
I can't add any positive advice as everythin I would have sugested you've tried. However I can tell you that the only warning my alternator gave was my lights dimming occasionally, and your right it was expensive 190 dollars imagine some of the high perf. stuff you could get. :shrug:
 

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Hardcore GL Tuning
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95 Posts
Just a suggestion...

Well, you checked everything...yes and no. The only piece of equip I think you forgot to check out is the VAF! I made the mistake of getting some carb/choke cleaner on mine and it died! Basically I had the same problems you have-- rpm drops/fluctuates and lost power when on the gas (until WOT and even then it ran crappy). I would definately check your VAF for proper functioning. When mine went out, I noticed that the gate partially closed (it shut fully), and the idle dropped, until the vacuum built up and forced it open, then the idle picked up again.
And alternator, schmalternator. The VAF cost something like $350 brand new and a used one can be somewhere around $80. Other than this, I would inspect the VAF to Throttle body boot for cracks and holes; as well as all vacuum lines.
Good luck! :1poke:
 

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Probe Member
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106 Posts
Discussion Starter #4
Hmm, the VAF. I really hadn't thought a lot about that. I popped the black top off and tightened the vane spring tension a few months ago. Perhaps when I sealed it back up I didn't get enough silicone in there and water leaked in the next time I washed my engine. I guess I'll pop it off again and see if there's any rust or corrosion this week. If anyone else has ideas, post them please.
 
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