Today, I decided since my car has 147k miles on the clock, I would clean out the carbon in the engine using seafoam through the vaccum line that goes to the brake booster. I covered it partially with my thumb as I had read elsewhere on this site, kept the car running and poured in about a 1/3 of a can of seafoam. I then let the car sit for 5 minutes and started it up. I let it run and very little smoke came out, however the car seems to me misfiring terribly. I checked the spark, and there seemed to be little to no spark comming from the top two posts on the coil pack. I went and bought a new coil pack, and there now appears to be weak spark comming from those posts. The car is running very rough, acceleration is very slow and the motor is bogging badly. I changed the spark plugs and wires less than five thousand miles ago. Is this a coincidence that it occured today while doing the seafoam, or is this a side affect of seafoam? Any suggestions would be greatly appreciated. Also there is no SES light on, which I find strange with the car running so bad.

Today I changed the plugs, and reset the computer. The car now seems to be running just as bad, maybe even worse. Car has bad vibration at 1500-2000 rpm when locked up at highway speed, very slow acceleration and terrible idle. Any other suggestions would be greatly appreciated.

If your car had much carbon, I might suggest a clogged cat. But since you are 92 and likely EGRless, I doubt it. Maybe you're not. Is your upper intake tan or black? Tan means no EGR.

Sounds like my old 93 Olds 88 in which I gave up on. I changed the plugs, wires, fuel filter, injectors, and coil packs. My dad owns it now and it still runs like sh*&t. probably a transaxle problem. My suggestion, buy a L67 powered car. A 94-99 Bonneville.SSEi would be perfect.

Well, if it'* bad at idle, it'* not a tranny problem. So we can rule that out. You've changed the plugs, so they should be fine. Have you got a voltmeter? Take off all the coil packs and test them. Specs are in tech info for good coils.

I'd get a 93.

Definately no egr, its tan. This problem started when I disconnected the large vaccum hose that goes to the brake booster to slowly add the seafoam, hasnt run right ever since. Any possible TB problems the seafoam could have cauzed? I dont give up that easy. If it was snoing here every other day, id drive the monte, which with 400+ hp isnt exactly snow/ice friendly. I need some ideas, im ready to pour in more seafoam to see if it unclogs something..I am at a total loss.

I wouldn't try more Seafoam just yet. The stuff shouldn't have gotten out into any sensors, so I would assume all the TB electronics are fine. Did you get the vacuum line hooked up tight? I suppose you could have a bad vacuum leak if it'* loose or cracked.

Think the brand new coil pack could be bad? its the one piece 6 post unit. I changed it yesterday when the problem started. The one thing I havent mentioned, is last night after I let the car sit for about an hour, the car ran MINT for about 5 minutes then the issue returned. Is there a way to test the leads that go to the coil?

The hose to the booster seems nice and plyable, but I will replace it tommorow, more ideas?

It is *possible* for a new coil pack to be bad, test that puppy. Take the brake booster line off and inspect it before replacing it.

I'm not sure what is making me ask this, but how'* your oil look?