motor loses RPMs

[88whitegt]

5.0 liter in a 93

I am having some major issues and I'm not sure on where to start. With the car just sitting there idling (idles rough, almost like it has a huge cam) and then rev'ing the motor up I lose RPM. I can rev it up to 3000 rpm and it'll drop to 2500 then right back up to 3000 and back down to 2500 etc etc, I changed the ignition module on the distributor and that didn't fix it, We noticed the car has a fuel regulator on it too which I'm hoping to take off soon but figured it wouldn't hurt to see what you guys thought.

Thanks in advanced

[blk93notch]

i would check the fuel pressure with a gauge and see what it does when you are reving it. also i would check the tps voltage also.

[John4cam]

vacuum leak? Dirty mass air sensor?

[Erics89GT]

bad iac sensor too

[John4cam]

bad iac sensor too

yeah, try cleaning it with some carb and choke cleaner. if the plunger moves freely then it's not stuck.

[torqueboxer]

Ill go fuel pump/ filter.

[Terminated]

I would do one step at a time and see if it works. Don't start doing a bunch of the above mentioned things cus then you don't know which one will/won't fix it.

My guess is something in the air delivery/vacuum.

[jaa55]

Ive rode in the car with him, hes losing ignition somewhere....he changed the ignition module already...the tach literally drops off when it starts to stumble.

[John4cam]

Ive rode in the car with him, hes losing ignition somewhere....he changed the ignition module already...the tach literally drops off when it starts to stumble.

Is it happening under load?

[88whitegt]

Yes under load. Suppose to be a nice weekend so ill hopefully have some time to mess with it.

[Dan B.]

Watching with interest....my HO T-bird is doing almost the exact same thing!

[88whitegt]

If anyone cares, I had a bad distributor, my buddy has a 5.0 in storage that we took it off of and now the car runs great.

[shockstang]

Glad you got it figured out. Those kinds of problems drive me crazy.