87 Carrera, two "problems"?

[Roger Shultz]

My 87 Carrera which I've had for going on 3 years is a pretty decent edition after lots of fixing of small stuff plus new clutch and total AC system replacement. It does not leak or burns oil. It runs smoothly with two exceptions.

When first started for about 2 blocks or so it has what I call the "herkie jerkies", not severe but just not smooth. It seems I have to give it a bit more gas than normally would be needed to accelerate. It does this both summer and winter. After a couple blocks and shifts, it is fine.

The second question (problem) is that as I run it hard through the gears, at about 3000 RPM there is a momentary drop in power, just very momentary, not severe but annoying. It too is not temperature related.

I've considered both just part of the car's personality and they have remained constant over the 3 years and about 6K miles. So, my question is, are these related and what might be the cause? I can't find any record of fuel filter change nor fuel pump replacement in the substantial service records that came with the car.

Thanks for any and all advice/opinions/direction.

Roger

[warner53]

I am no pro. My 86 herked and jerked for a while until I checked the distributor cap and found the contacts carboned up. Plus I would check the wires in the dark for mis fires.

Luck

[twistoffat]

Time for new plugs perhaps.

[wwest]

Originally Posted by Roger Shultz

My 87 Carrera which I've had for going on 3 years is a pretty decent edition after lots of fixing of small stuff plus new clutch and total AC system replacement. It does not leak or burns oil. It runs smoothly with two exceptions.

When first started for about 2 blocks or so it has what I call the "herkie jerkies", not severe but just not smooth. It seems I have to give it a bit more gas than normally would be needed to accelerate. It does this both summer and winter. After a couple blocks and shifts, it is fine.

The second question (problem) is that as I run it hard through the gears, at about 3000 RPM there is a momentary drop in power, just very momentary, not severe but annoying. It too is not temperature related.

I've considered both just part of the car's personality and they have remained constant over the 3 years and about 6K miles. So, my question is, are these related and what might be the cause? I can't find any record of fuel filter change nor fuel pump replacement in the substantial service records that came with the car.

Thanks for any and all advice/opinions/direction.

Roger

Carbon "tracks" inside the distributor cap moistioned via condensation. Condensation evaporates away with engine heat.........

[Tippy]

Sounds like 1, small vacuum leak or base idle settings need to be reset due to Motronic degradation 2, possibly a worn spot in the airflow meter resistor track.

1 should solve cold running
2 should solve 3000 RPM flat spot

[steely]

+1 - The possible vac leak and the worn AFM track were my 2 thoughts as well.

You could hunt those down or just replace the lines, and test the AFM pot/wiper as you sweep it's full range.

[Roger Shultz]

The distributor cap was replaced on purchase, plugs are unknown. It idles fine at all temperatures after an initial warm up period starting at about 1100 then quickly goes down to about 850-900 but steady. Vac leak maybe, but never after a minute or two and never after that.

The AFM if it has some sort of pot asscociated with it sounds likely. I will get educated on where that is and see what I can learn, THANKS!

[stlrj]

Originally Posted by Roger Shultz

When first started for about 2 blocks or so it has what I call the "herkie jerkies", not severe but just not smooth. It seems I have to give it a bit more gas than normally would be needed to accelerate. It does this both summer and winter. After a couple blocks and shifts, it is fine.

The second question (problem) is that as I run it hard through the gears, at about 3000 RPM there is a momentary drop in power, just very momentary, not severe but annoying. It too is not temperature related.

Both problems could be mixture related. Overrich could cause rough running when cold that clears up when the 02 sensor warms up. It could show up as a bog at 3000 RPM too. Not uncommon for late 3.2s to go rich with time.

[Germanator]

I had similar issues, turned out to be the temperature sensor.

[PatrickB]

Could possibly be fuel injection as well. New injectors at 135k mile on mine, essentially made it perform like it was a brand new motor. Cheaper to remove them and have overhauled, than buying new. And sorry gents, a bottle of Techron ain't the same as an overhaul!

Do the easier cheaper stuff mentioned above. With mine, the issue was similar, being very intermittent, even at different rpm's/loads, engine temps, and outside air temps. Often times, I wouldn't be able to get the issue to repeat under exact same situation. Also, MPG's began to worsen... I hate just "throwing" money at an unknown problem, expecting results! However, a F.I. overhaul, if never done, SHOULD be done. Your car WILL run better, and get better fuel mileage as well.

[Roger Shultz]

The answer to my two problems turned out to be resolved with a valve adjustment and likely the main problem was the O2 sensor. After the valve adjustment, the O2 sensor was disconnected as a test and the car ran strong, no hesitation when "cool" nor around 3000 RPM as I initially reported. I intended to change the O2 sensor myself however since it appeared never to have been changed in 135K miles, not only were the catalytic converter shield bolts a mass of rust, the O2 sensor ultimately was frozen in place. I took it to PowerTech in Rockaway, NJ who solved that problem and the car now runs very well.

Thanks to all who responded with ideas and to Pelican for hosting this wonderful resource!