misfire and o2

SANGUINE · October 15, 2014

So I had a #2 misfire and it was idleing rough and sputtering. I found the plug wire was melted. I put new plugs on it. Then I got a #4 misfire. I replaced the plugs which were really old. Then now I have a #2 misfire again and a supposedly bad o2 sensor. I have codes p0140 and p0302. It runs pretty smooth. Tad bit rough but not bad. When cold it has 60 on the oil pressure gauge. Once warm about 50 and at idle lowest was just over 40. Before plugs it stayed just under 40. I changed the oil, have new gas. The coolant has gone down in the last 70 miles from the full line to halfway below the low line and empty. Can I get some help here? I just bought the truck and I can't get it to pass inspection. Oil has not gone down.

SANGUINE · October 15, 2014

Can't believe I forgot to post vehicle. It's a 98 k1500 4x4. Lifted 6" which makes it a pill to work on. I have to fix it by friday.

SANGUINE · October 17, 2014

C'mon y'all. Can't I get any suggestions?

00Silverado4x4 · October 17, 2014

If you are losing coolant I would be looking into getting your engine pressure tested for a possible head gasket leak. If your oil level is staying at the same level than you must have an external coolant leak...fortunately. Do you see any stains around the bottom of the heads that may look like something has been leaking? As for the misfire I'm not entirely sure what to suggest there except to take it to a dealer/shop to have it diagnosed so you don't throw unnecessary parts at your truck.

SANGUINE · October 17, 2014

I did the distributor cap and rotor today. It needed those anyway. So far it backfires a good deal. Something I did that may not have been smart is I cleaned it today. There are 2 places. Looking from the front back, the drivers side head towards the back there is a rubber hose that goes into the head. It was pulled out some and had spewn something around it but I just pushed that back in so that's not a issue. On the other side there was a stain or sorts in the dust on it towards the front on that side. I'll look to see if there's anything in that area that could be leaking.

SANGUINE · October 17, 2014

It wasn't actually leaking anything. I made a mistake. I didn't notice the cold and hot on the steering fluid and the coolant. So I over filled it. My bad. Coolant is a bit low but no biggie. Now after cap and rotor it backfires. Does it maybe once every 10 secs or so