Plug replacement

[dj1111]

My daughter is looking to purchase a 96 Monte Carlo from a friend. The thing is in great condition. Only exceptions are poor and surging acceleration and it needs new exhaust. She left the car with me this weekend and the first thing I looked at are the spark plugs and wires. Pulled out the first plug and wow, the worst I've ever seen. Pulled out another and it look the same. The center electrodes are worn to a point. And the gap at the pencil sharp point is around .07" ~ .08". So my question is, how bad (frustrating) of a job is it to replace them? The rear ones that is. If I could see them without using a mirror and a flashlight I'd be out there doing the job without question. Thanks for any help.

['97ventureowner]

Better access to the rear plugs can be achieved by "rolling the engine forward" on these vehicles.

[dj1111]

Getting impatient I got out some tools and went at it. Turns out it wasn't that bad. I used the spark plug socket, a 6" 3/8 extension, a 1/2 to 3/8 adapter and a 1/2 ratchet. Used the 1/2 ratchet to get better leverage. Not much room back there. As it turns out the plugs may not be the problem. The electrodes are supposed to be pointed. Some Iridium 100,000 mile plugs. So if it isn't the plugs does anyone else have any suggestions? The symptoms: Poor gas mileage and terrible acceleration. It starts out in 1st gear fairly strong but when it shifts into second it barely accelerates any more. The engine chugs and sputters.

[ChevroletTough]

you need the exact extension length. Its doable, ive done it on 3 monte's. Make sure to electrical tape the extensions and socket together, so they don't come unhooked down in there!

[abaird]

Could still be a misfire under a load caused by a bad plug or wire. Just because they don't look bad doesn't mean anything. Is the SES light on? Also take a flashlight and look for coolant puddled up under the throttle body. I'm assuming it is the 3.1 they are known intake gasket failures. If it is the 3.4 DOHC, run away as fast as you can.

[dj1111]

It's a 96 Monte with the 3.1 engine. The thing has been running like absolute crap during warm up. The running like crap only happens under load (acceleration). I was at a loss so I had to resort to bringing it to the only shop I trust. The first thing they fixed was to replace the exhaust manifold at the rear of the engine. We thought because the was in the immediate area of an oxygen sensor, replacing it may fix the poor performance. Well after replacement and everything was quiet we found the engine has a very bad knock when cold. And it still ran like crap. They did a lot of testing of temperature sensors, air flow sensors and ox sensors and everything checked out ok. So they took the thing for a ride with the computer connected and collected a ton of data. What they found was all the noise the engine is making (mostly piston slap they said) is causing the knock sensor to retard the timing. A lot. I believe he said up to 18 degrees. Once the engine warms up and most of the noise is gone, it runs like a top. If you disconnect the knock sensor, the thing runs great when cold. He gave me some suggestions of things they could try but it all sounded like expensive but educated shots in the dark. So these are my questions. Could it be as simple as the sensor is old and hypersensitive? It's an easy replacement. Or should I look at running heavier oil than recommended? Like 10w30 or 10w40. What about any oil additives that actually work? The mechanic also recommended a professional fuel system cleaning.

Oh I almost forgot, no SES lights during this ordeal.

[Will Help]

10w30 is the same viscosity as a 10w40. They flow like a 10 weight but, with different oil quality and additives, they protect like a 30 or 40 weight.

You would have to go to a 15 w? or 20w? to get a thicker viscosity index. these are available through most major brands. I would also go with a synthetic blend or full synthetic to help reduce the friction wear on the wrist pins. I had a 3.1 with over 350,000 and now have a 3.4 with over 180,000 and have had no problems with wrist pin or piston slap. Bought both vehicles new and received a recall on the 3.1 at 75,000 miles about the wrist pins. Never had to take it in. I used nothing but synthetic oils in both with a high end anti drainback oil filter. I still use 5w30 synthetic.

PS: Bicycle gets you 912 miles per gallon of sweat!!!

[dj1111]

5w30 is the recommended that's why I suggested 10w30 or 10w40.

[Will Help]

That would be OK if the weather were still cold. In warmer weather I would lean towards more cushion of higher viscosity on a loose engine.