I'm stumped (which is hard to do.)

[SexySilhouette]

1995 Olds Silhouette. L27 3.8 N/A with 159,000 miles.

In park or neutral, it's smooth as butter at any RPM. In drive with the brake on, it's smooth at any RPM.

In drive moving and more than 2000 RPMs, it breaks up like nobody's business. Misfires like crazy (at least I am quite sure it's a misfire.)

I've run EFIlive datalog and found nothing abnormal.

Any ideas?

[Duke George V]

Well, drivability issues are almost always one of three things lacking: fuel, air, or spark. When did you last do a tune up?

[86euro]

Does it only do it under heavy load? Can you get it to act up in drive while stopped, with foot on the brake and gas?

[SexySilhouette]

Well, drivability issues are almost always one of three things lacking: fuel, air, or spark. When did you last do a tune up?

About 8 months ago.

Does it only do it under heavy load? Can you get it to act up in drive while stopped, with foot on the brake and gas?

Yes and no. Cruising is fine, accelerating is when it acts up. It does not do it standing still in park or drive.

[Duke George V]

Clogged MAF? Maybe a bad TPS?

[SexySilhouette]

I'll check the MAF...I would think the either one would throw a code though. I replaced the TPS when I did the tune up. This just started about a month ago.

It passed emissions though...Super low emissions. I was surprised. The girl that does the test asks me every time how I keep my old cars like that.

[86euro]

I will guess crusty terminals on a coil pack or two, or maybe a clogged fuel filter.

[Duke George V]

Fuel pump might be going too. I had a similar problem on a truck at my previous job, where it would be fine at light throttle, but would just fall on its face if you gave it the beans.

[SexySilhouette]

Fuel pump and filter have also been replaced within the past year.

I'll check the coils. I found a bolt that had come from somewhere and fallen in between the terminal posts on a coil.

I just replaced the battery (free optima redtop!) and cleaned the MAF but haven't driven it yet. Maybe later.

Thanks guys!

[Jr's3800]

Would you happen to have another Ignition Control Module laying around?

These engines were very clean emissions wise... If the engine is in good tune and the cat is happy the emissions will be very low...

[Century7667]

Would you happen to have another Ignition Control Module laying around?

These engines were very clean emissions wise... If the engine is in good tune and the cat is happy the emissions will be very low...

That's my vote. Especially if the problem is under load at higher speeds.

Ken T.

[SexySilhouette]

A new set of wires took care of the problem. The last set must have been defective.