missing and fast idle

[Fire_Burb]

I have a problem that is driving me nuts, but I'll give a little info and history that might help with a solution.

1990 Suburban 2500 454 TBI 182,000 miles, approx 80,000 on rebuild.

I purchased the vehicle and on the test drive, everything was great, ran fine, sounded fine, tons of power, etc. I checked the oil after the drive and it was a bit low, (as expected after driving) and clean, but not new. Transmission fluid was also low, but again, a 19 year old truck used for towing pretty frequently so I wasn't worried. Adding that to the great price and I bought it. Drove it home without incident and parked it.

A week later went to get parts for a tune-up and going around a corner the tranny slipped. ok, so it's a little bit lower than I thought. It also occasionally would idle high at a stop light and was missing yet whenever it idled normally it did so smoothly. I grabbed some fluid, oil, filter, plugs, etc and headed home after putting in the fluid. On the way home sitting at an intersection the thing all of a sudden decided to fill the street with so much smoke, I couldn't see the traffic light. Got it home and let it sit to cool so I could change everything.

I checked the oil again before I changed it and not only was it not low, it was about half an inch above the full line. When I drained it and measured it out the truck had 9 quarts of oil in it plus what was in the filter. Now I'm worried that they changed the oil without draining it and I just blew a ring, or valve guide.

I also changed the plugs of which none were fouled, but I did notice they had accell wires on it (red to match the truck) but for some reason cut the boot off right at the metal clip on every plug. I figured this was the source of the missing so I put new wires on my next shopping list.

Drove it around for almost a month, (no time or money to get the wires, but I had to drive it to get to work. Problem was every other time I started it, it would smoke like crazy and I verified it was doing so out of the tailpipe. Then all of a sudden it slipped on a corner again. I checked the fluid levels and the transmission was way low, oil was fine. Turns out the vacuum modulator was bad and it was sucking the tranny fluid back up into the intake and that was the source of the smoke.

Here's the current situation. I've again changed the plugs, and changed the wires, rotor, and cap. It will still idle high and miss like crazy then all of a sudden I'll pull up to a light and it'll idle down and purr like a kitten. Next light it'll be up high again. I'm wondering at this point if burning all the tranny fluid may have fouled the converter. I can't think of what else would cause the high idle (at which point you can smell it's running extremely rich), but am stumped on the random missing.

now if you've actually read through all this, I hope you have some ideas on what I could check next.

-mike

[unplugged]

vacuum leak. search these forums: vacuum leak random misfire. lots of good info.