So I've had this 1996 SE7 for almost a month, and it's developed an issue.

Been running fine so far, but all of a sudden in the last week, it seems that while it's in D, it can't get out of it's own way. Absolutely no power. Goes like gang busters up to about 1800 rpm (Scanguage installed), then just starts sputtering, complete loss of power. When it does manage to get rolling, it'll eventually break over the 2k rpm mark, but by this time, I'm going 50.

If I floor it at any point, sputter sputter sputter.

If I'm sitting in the drive in P, it'll rev up to 3k easy, no sputter or nothing.

Codes that I pulled were P0125, P1193, P0158 and P1138. But, once I cleared them, they haven't come back.

Thanks in advance.

Thoughts?

-Indy

 

Throttle position sensor

should show 9% or so at idle, smoothly moving up as pedal pressed. If bad, ECU uses a default value

 

So when in Park, TPS is a non factor?

 

No, when it is in park there is so little load. You may find a number of things that need a good cleaning, including PCV hoses from each valve cover and whereever they plug into, IACV (use carb cleaner also, don't play with the tip, just squirt it), the throttle body butteryfly valve; MAF (clean only when cold, key has not been turned for 8 hours - makes it 350F inside) with made-for-MAF spray. These are the cheap fixes, then you move on to replacing O2 sensors, etc.

 

Unplug the VSS and see what happens.

 

Good point, if bad it triggers staged shutdown of engine to prevent operation above escape velocity. So when sensor is bad, this is triggered at lower speeds instead of 114 mph. Unplugged will have no cruise or speedometer.

But I would think if you floor it at very low speed, and it does this, you may not have reached the speed where the VSS acts up, it is not based on rpm but on speed of the vehicle.

 

Update today driving in to work. Seemed 'ok'. Not quite like crap. I had the UltraGuage monitoring TPS and IGN. TPS was going up to 48 on occasion (I was going 70), and Ign seemed to be at least bouncing around.

I will watch tonight on the way home to see what it does.

 

Well, I'm beginning to think not TPS.

I monitored both TPS and IGN on the way home and then on the way back to work this morning. TPS seemed to be functioning (according to Scanguage) as it should.

What I did notice, was that under 'load' from a stop or going slowly, IGN would normally be at say 20, when I would give it the beans, it would stay at 20, maybe even drop to 18 or so, but then after it stopped sputtering,coughing and all that and got up some speed, IGN would then jump up to say 30-40ish?

That normal?

Any other ideas?

 

Unplug the VSS and see what happens.

The actual speed of the vehicle is irrelevant if the VSS is defective.