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I have a 97 4.6L bird with ~97k miles on it, and for the last month or so it occasionally idles rough (car shakes sometimes while at a stop light). It also feels like it hesitates/misses and is a little clunky feeling under heavy acceleration.

I've had it checked out by multiple shops and have had maf cleaned, new plugs, and injectors cleaned. I had one shop tell me it might be low compression. Any ideas? Thanks in advance.
 

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I have somewhat same (plus some additional) symptoms in my car. Maybe I'll get my answers here and don't have to start another thread. Sounds like an air leak, but let's hear the professionals first.
 

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Numerous possibilities.
Here are just a few:

My '96 was exhibiting the same behavior, then came the misfire DTC's, which led to my thread about fouled plugs, which led to my thread about the PI intake swap, which I'm very close to doing. Reason being a water leak due to [likely] cracked plastic intake manifold (could be a bad gasket, but the intake is old enough to have cracked by now). If your intake hasn't been replaced, it's probably cracked.

Have you looked for moisture around your plug boots/holes? Examine it carefully with a good light source, as you may not spot it right away. Have you noticed any antifreeze drippage on the floor/pavement?

If your heads/block are bone dry, then you could have a sticking IAC. You can easily remove it and clean it with carb/choke cleaner -- you'll be able to tell if it's sticking by carefully pushing on the rod inside the housing (after it's been removed from the car) with a flat blade screwdriver or needle nose pliers if there's no notch for the screwdriver to grab. Don't force it too much or you can damage it.
Aftermarket IAC's are known to fail/stick prematurely, especially the economy (house brand) ones.

You could have dried up vac lines. Check them for cracks.

You may simply have bad plug wires. If yours have never been replaced, it's past due with your mileage. Pop the hood and wiggle them around at idle and see what happens. Check for dried/cracking insulation. Check for moisture on the cables. They could just be routed incorrectly, too.
The shop should have put contact grease inside the boots when they replaced the plugs, but not everyone thinks to do this (or are just lazy). You may have intermittent/corroded contact in there.

You can also check compression with an inexpensive, widely available tool. The shop should have done that as part of their diagnostics.
 

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Thanks for the response. I have replaced the intake manifold. I'll check into a tool to check the compression. The wires aren't original, but I haven't changed them since I've owned the car and have driven it 50k miles. They look fine to the naked eye but that's something I'll look into.
 
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