[rainbowmustang]

1997 Mustang GT, 4.6L 2V. Everything stock except K&N air filter. 80,000 original miles, 5 speed manual.

Engine starts without any problem, and after a trip to town (about 10 minutes) I turn the car off. Come back to the car, starts without any problem. However, my idle speed is about 100 rpm lower than normal. Upon driving now, the car does this bucking feel, like if you were to push and release the gas pedal (only in 1st & 2nd gear). At any sustained speed, whether it be 30mph or 70mph, applying the gas pedal just a little bit the engine bogs down, like it's misfiring or something. Once I push the pedal to the floor, It revs up and takes off and does not miss or bog or run rough. After 5-10 mins of this erratic running, it clears up most of the time. It has done this both at 60 degrees outside and 10 degrees outside. I have no MIL light on, no codes, and everything appears to be operating correctly. Anyone have any ideas? The car idles fine, spark plug wires are not shorting out anywhere, and has new spark plugs. A friend of mine works for Ford and says its the IAC valve. But, if it was it would be affecting my idle. The car has never stalled, never died, just has severe hesitation like. Thank you in advance!

[Boomer]

Sounds like a dirty MAF sensor.

[rainbowmustang]

Thank you for your input... Wouldn't a dirty MAF sensor trigger the "Check Engine" light? Or is it just dirty enough to cause my problems but not enough to set the light? As I mentioned in my op, the check engine light is NOT on.

[Casper98GT]

If it just started it might not have a chance to set a code. Could be misfire, could be MAF sensor, but normally along with the bad running you should be setting a p0171/174 code. If you have a buddy at ford, have him use the IDS and run a KOER or KOEO test to it and see if anytihng is pending.

[nHuman]

lol sounds like my 96

Cept im throwing a MAF code

My maf went to shit every since i put a damn cheap intake on it.

Need to buy a new MAF sensor but they like 70 bucks at a junk yard and im scared if i get it and it dont fix nothing i'll be pissed, lol

[rainbowmustang]

Here's an update! I took out my MAF sensor and did not see any visible dirt, even under magnification. I did clean it according to the instructions on this site. Let it dry thoroughly (several hours) and reinstalled. I took the car out driving a few times, and after about 50 miles it started doing the same thing again. Cruising speed, whether 30 or 50 or whatever, bogs down when applying the gas slightly. I do have a bucking in 1st and 2nd gear, and just bogging down, like the ignition is misfiring. My buddy at ford works at a dealer two hours away. I had it scanned and checked out and there was nothing pending. So, I am kinda stumped. My only thought is maybe the spark plug wires or plugs are doing something funky? I'm thinking of just replacing them (I think the wires are original) and would like to know of a good decent of wires to put in it. I've looked at livewires, but too pricy for me right now. Any recommendations on a good platinum or double platinum spark plug? Autolite maybe? Thanks for your help guys! You guys are awesome!