Rough idle, poor performance
PHurst
09-10-2004, 03:10 PM
Howdy, first the introductions, as am new here, I was unaware that there was a Caprice board out there aside from a couple for LT1s only. I have a 92 caprice with a 305, just over 210,000 miles. I inherited the car from my grandfather, who took super good care of it, and it shows. Car still has original engine and tranny, and has been absolutely problem free for the last 3 years. Now I have started having problems, and have done some of the basic stuff myself, but I find that I now need to solicit the advice of those with more experience. Here's what's happening:
Car cranks just fine, and idles fairly smoothly in neutral, but once I put it in gear, it idles rough, sounds like it's missing, and I can smell what I assume is unburnt gas in the exhaust. Just sitting in gear, it will run rough for 5 or 10 seconds, then be smoth as silk for a second or two, then runs like crap again. When accelerating it gets somewhat worse, is getting terrible milage, and power feels about cut in half. Stutters mostly, but sometimes runs like a top for a few seconds at a time. This condition is worse under accelration, but is still there when maintaining a constant, speed, only not as bad. I have done the easy basics, replaced air filter, fuel filter and PCV valve. When I was fiddling around under the hood last night (after dark) I noticed that I could see some arcing in the ignition module/coil/distributor area. I checked the wiring in the area, and noticed 2 of the wires between the ignition module and the coil had some cracks in the insulation, so I taped them up. Things were better, but I still had the problem, and still could see some arcing. I see it mainly between the coil and the mounting bracket, and some very faint arcing between the plug wires where several of them lay on top of one another right up near the distributor cap, particularly from the wire between the coil and distributor. There is also a ticking noise coming from either the coil or distributor, I can tell since they are right next to one another. I have put my finger on both, and can't feel anything, so i don't think it's the rotor hitting a contact or anything,I suspect it's the sound of the spark arcing. Is it normal for there to be any arcing in either of those places, or am I due for a new coil and wires, and do you all think this is the source of the problem? If I need to replace them, do any of you have any suggestions for doing it? I would have already, but some of the plugs are in next-to impossible to reach areas, and I can't see any way to get to the second bolt on the coil bracket.
Car cranks just fine, and idles fairly smoothly in neutral, but once I put it in gear, it idles rough, sounds like it's missing, and I can smell what I assume is unburnt gas in the exhaust. Just sitting in gear, it will run rough for 5 or 10 seconds, then be smoth as silk for a second or two, then runs like crap again. When accelerating it gets somewhat worse, is getting terrible milage, and power feels about cut in half. Stutters mostly, but sometimes runs like a top for a few seconds at a time. This condition is worse under accelration, but is still there when maintaining a constant, speed, only not as bad. I have done the easy basics, replaced air filter, fuel filter and PCV valve. When I was fiddling around under the hood last night (after dark) I noticed that I could see some arcing in the ignition module/coil/distributor area. I checked the wiring in the area, and noticed 2 of the wires between the ignition module and the coil had some cracks in the insulation, so I taped them up. Things were better, but I still had the problem, and still could see some arcing. I see it mainly between the coil and the mounting bracket, and some very faint arcing between the plug wires where several of them lay on top of one another right up near the distributor cap, particularly from the wire between the coil and distributor. There is also a ticking noise coming from either the coil or distributor, I can tell since they are right next to one another. I have put my finger on both, and can't feel anything, so i don't think it's the rotor hitting a contact or anything,I suspect it's the sound of the spark arcing. Is it normal for there to be any arcing in either of those places, or am I due for a new coil and wires, and do you all think this is the source of the problem? If I need to replace them, do any of you have any suggestions for doing it? I would have already, but some of the plugs are in next-to impossible to reach areas, and I can't see any way to get to the second bolt on the coil bracket.
93 CAPRICE LTZ 5.7
09-11-2004, 01:21 PM
You are due for plug's and wires!
Unless you know your firing order replace one at a time! It's actualy easier to get to your plugs from under your car so your need ramps or jack stands!
Also since your there replace the o2 sensor!
Your coil is most likley ok I wouldn't replace it just yet! Keep track of which plug came out of which cylinder.They can tell you the conditon of each cylinder and let you know of any problems that you may be unawere of!
Unless you know your firing order replace one at a time! It's actualy easier to get to your plugs from under your car so your need ramps or jack stands!
Also since your there replace the o2 sensor!
Your coil is most likley ok I wouldn't replace it just yet! Keep track of which plug came out of which cylinder.They can tell you the conditon of each cylinder and let you know of any problems that you may be unawere of!
PHurst
09-13-2004, 09:04 AM
Thanks, I appreciate your taking the time to reply. I'll go get some plugs and a wire set after work today, now I just need to find a friend with some ramps :smile: . Sghould I go with OE plugs, or has anyone had any success with platinum or other specialty/performance plugs? Also, is it ok to drive this way for a couple more days?
PHurst
09-13-2004, 11:49 PM
You hit the nail right on the head, new plugs and wires did the trick. She's running like a champ. I must say, they realy crammed a bunch of sh*t under the hood, some of those plugs were a real PITA to get to. Well, what's an automotive project without a little bloodshed :iceslolan .
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