Trying to eliminate erratic idle and miss in 87 245 with 225k miles, I did a variety of maintenance items and beyond - filters, cap, rotor, wires, plugs, check vacuum leaks, clean throttle body (it was dirty), new throttle switch (full of oil and failed the diagnostic test), new injectors - and still no power from #1 cylinder, as the savvier among you may have already guessed a vacuum leak at the intake manifold was the culprit. Replaced intake manifold gasket (which was clearly bad - should have done the carb cleaner spray test first!) and while doing that replaced breather box which seemed to be plugged but on inspection I think just the pipe coming off the top was lined with deposits.

So then it really ran nice & I felt pretty happy about the whole obsession - except, before the new intake manifold gasket arrived I was doing an errand and a block from my destination it dropped to low power, I could only go about 10 miles an hour. Went the remaining block to my destination & left the car for about 15 minutes - came back and drove away with full power.

I was trying to think what caused this before it should recur & checked the sock filter on the in-tank fuel pre-pump & it looked real clean. I could hear sound from it when running the car - it's a wagon so I could start it and then listen to it fairly easily.

It has since happened a few times. Once right after heading out and fairly cold - drove a few blocks, went up a hill and it went away.

After reading the archives some more, I came to suspect the catalytic converter. The exhaust is about 2 year old ipd replacement. The noise seemed to be something like the descriptions.

I pulled the converter off today and it appears ok - no loose rattling - can see light through it, slightly.

Any thoughts? I'm losing my motivation.

Regards, Thanks, Joe