JBuckley Posted September 23, 2004 Report Share Posted September 23, 2004 I know this is not a Caddy question but your knowledge will sure help. I have a 92 Buick Lesabre, 3800 engine, was running fine, yesterday my wife was dropping a friend of and was talking with the car idling, all of a sudden it developes a miss/ very rough idle. It was shuddering and missing when trying to accerate from a stop sign. I changed plug wires last night no help. Got up this morning went to work on car and it idled and ran fine, drove around for 10-15 minutes everthing ok, went home turned it off came out in an hour and now it is idling rough again. No codes in computer, check PVC valve ok. any other ideas group? John Link to comment Share on other sites More sharing options...
Scotty Posted September 23, 2004 Report Share Posted September 23, 2004 Its somewhat intermittant as it was OK this morning. Does this engine have a distributor cap, I would check the cap and rotor if it does. Look for carbon tracts in the cap and cracks. Look at the engine in the dark for arching around the coils if it has coil packs and arching around the plugs maybe you have a plug fouling up. When was fuel filter changed. Listen for vacuum leaks check all hoses for cracks. Link to comment Share on other sites More sharing options...
johnnydone Posted September 23, 2004 Report Share Posted September 23, 2004 try checking out the module inside dist autozon usually checksv them for free just a thought Link to comment Share on other sites More sharing options...
67coupedeville Posted September 23, 2004 Report Share Posted September 23, 2004 I would start with the plugs and fuel filter and everything else Scotty said, but not the cap and rotor because it does not have one . It will have a cap but it is a rectangular shaped box on top of the motor. Check for cracks in it. The easiest thing to do, that I would do, is put a tank a premium fuel in. My dad had a 1986 Olds Toronado with a 3800 and it would run and idle and spit and sputter with regular, put in a tank of premium and it would run smooth and perfect. Only thing is you have to keep putting premium, which I do in all our vehicles. I figure it keeps injectors from becoming bunged up. Spence Link to comment Share on other sites More sharing options...
Logan Posted September 23, 2004 Report Share Posted September 23, 2004 The 3800 does not use a distributor. It uses direct ignition. You may have lost a coil pack. There are 2 versions of the direct ignition system used on the 3800 of that era. A Delco unit and a Motorola set up. One version uses individual replaceable coils, the other has the 3 coils built in to a single replaceable 3 coil unit. Sometimes....you can lose the actual ignition module. Logan Diagnostic LLC www.airbagcrash.com www.ledfix.com www.ledfix.com/yukontaillightrepair.html www.ledfix.com/ledreplacements.html www.ledfix.com/j42385toolrental.html Link to comment Share on other sites More sharing options...
Scotty Posted September 23, 2004 Report Share Posted September 23, 2004 I think I had a 3800 in an 88 Pontiac Bonneville, I didnt think it had a distributor but it did sound like an ignition problem. I used to have lots of problems with the MAF on that car and it would run really horrible hesitating at all speeds. Link to comment Share on other sites More sharing options...
Ranger Posted September 24, 2004 Report Share Posted September 24, 2004 Hows your coolant level? The 3800's are notorious for upper intake plenum & gaskets going bad. Also lower intake manifold gaskets but not as much. Just did my wifes a month ago. They are not a question of if, but when they will need replacing. A bad coolant leak might casue the rough idle though I would not think it would be intermitent. Link to comment Share on other sites More sharing options...
RJSUS Posted September 24, 2004 Report Share Posted September 24, 2004 I had a 3800 in my 91 Riv.....Car has 235000 on it and still running....I had that exact problem at 90000 miles.....My event was caused by coil pack problems....The cost is steep...I was able to search thru internet salvage suppliers, looked for the best warranty and ordered thru them.....Good Luck Link to comment Share on other sites More sharing options...
Logan Posted September 24, 2004 Report Share Posted September 24, 2004 I know the '92-93 had the older metal intake. Latter models about '95-96 went to the failure prone composite intake. The latter plastic ones will have to be changed every 7-8 years I suspect. I guess we will have to see how the aftermarket ones hold up. Logan Diagnostic LLC www.airbagcrash.com www.ledfix.com www.ledfix.com/yukontaillightrepair.html www.ledfix.com/ledreplacements.html www.ledfix.com/j42385toolrental.html Link to comment Share on other sites More sharing options...
Ranger Posted September 24, 2004 Report Share Posted September 24, 2004 I know the '92-93 had the older metal intake. Latter models about '95-96 went to the failure prone composite intake. The latter plastic ones will have to be changed every 7-8 years I suspect. I guess we will have to see how the aftermarket ones hold up. When I replaced mine, I machined a metel sleave to fit in the EGR port and a new "stove pipe" of a smaller diameter so I now have a .050 clearence around the "stove pipe" to prevent over heating and burning the hole in the upper. Should last the life of the engine now...... I hope. Don't want to do it again. Link to comment Share on other sites More sharing options...
KHE Posted September 24, 2004 Report Share Posted September 24, 2004 Larry, The plastic intakes did not appear on the 3800 engine until the 1995 model. His '92 has an aluminum intake. Did you install a GM replacement upper intake or an aftermarket part? There are some aftermarket intakes that have a revised EGR passage as well as structural improvements. Kevin '93 Fleetwood Brougham '05 Deville '04 Deville 2013 Silverado Z71 Link to comment Share on other sites More sharing options...
Logan Posted September 24, 2004 Report Share Posted September 24, 2004 I think theres a good chance a coil went out.....hopefully he has this setup with the individual coils. Prices are not that bad.... Individual coils are about $25. 3 coils in 1 version is about $75. Tha actual ignition module is about $125. My '92 Bonneville with the 3800 had the 3 coils in 1 version. Logan Diagnostic LLC www.airbagcrash.com www.ledfix.com www.ledfix.com/yukontaillightrepair.html www.ledfix.com/ledreplacements.html www.ledfix.com/j42385toolrental.html Link to comment Share on other sites More sharing options...
Ranger Posted September 24, 2004 Report Share Posted September 24, 2004 Larry, The plastic intakes did not appear on the 3800 engine until the 1995 model. His '92 has an aluminum intake. Did you install a GM replacement upper intake or an aftermarket part? There are some aftermarket intakes that have a revised EGR passage as well as structural improvements. OOPS, didn't realize he had an aluminum intake. Lucky guy! I tried to get a Dorman intake but all that was available was Delco (OEM) I beleive, but with my modification I should be in good shape. Link to comment Share on other sites More sharing options...
JBuckley Posted September 24, 2004 Author Report Share Posted September 24, 2004 Thanks guys, I am also leaning to the coil pack as the problem, I wish I had the 3 seperate coils, then I could buy one & swap around. I have no problems with the intake on this year make no fluid loss, it has 179,860 miles and is/was running strong until this little problem cropped up. This has been a good engine for me, I have had to only replace 2 alternators, water pump & tstat, hoses and all the normal wear and tear manintenance stuff, oh yes and that darn plastic water connector that comes out of the intake under the alternator. Gotta love this forum, the knowledge that is shared here is so wonderful. it has helped me with my Caddy, and now with the Buick. Is there a way to check out the coil pack? Since is the all in one unit, not the 3 seperate units. Thanks so much. John John Link to comment Share on other sites More sharing options...
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