2000 Lumina Needs Your Help

[Tracey1212]

Okay, what I've got is a 2000 Lumina 3.1 engine problem. Here are the details:

1. The engine has 135,000 miles on it.
2. Other than oil, filter, gas filter, air filter, pvc, and battery replacements, not much has been done to the engine. It has run well so far, until now.
3. Recently, it began to idle slightly rough.
4. As the engine warms up to normal operating temp, the rough idle gets worse.
5. At peak operating temp, about mid dial, or about 180 F, the car often dies.
6. When the car is cold, it is posible to press the accelerator and watch the Tach move up nicely though the idle is slightly rough when cold.
7. When the car heats up, it is not easy to push the Tach past 2000 without the engine wanting to bog down and if you let off the pedal after hard acceleraton while parked, the engine may drop rpms so fast that it dies, sometimes.
8. With STP carb and inject cleaner added, 2 bottles to 1/2 tank or gas, the engine runs smoother.
9. No check engine light or codes present.
10. When the car heats up at idle to normal temp, the exhaust sounds puffy and you can feel the missing in the engine by the fact the exhaust comes out in lessor or greater puffs.
11. With the STP added, at least when the engine is cold at startup, the puffs are not present at all period! The engine exhaust is very smooth as it should be.

So.....whats the chance this performance problem is related to wires or plugs?

Gotta get this fixed fast. All ideas welcome!

Thank you in advance...

[maxwedge]

Welcome to AF, bad plug, wire, injector, vacuum leaks, coil, low fuel pressure, can all cause a idle misfire/power loss. A full scan will look at pending codes and misfire counts may pinpoint the suspect cylinder/s, or sensor issues.

[Tracey1212]

Whatever the issue is, it is highly affected by engine temperature which is one of the key areas I hope will help pinpoint the problem. The scan is about100 dollars in my area, and Id like to avoid that if at all possible. I'm going to replace plugs and wires right away and see what happens. Any ideas about why temperature so affects the smoothness of the engine? When cold, its fairly smooth. When full running temp, its got a moderate miss that bogs the car when given lots of rpms.

[maxwedge]

Again, most issues as you describe tend to pop up hot, the catylytic convertor could be blocked also, but the misfire description is the first thing to chase, in a pinch disconnect the exhaust ahead of the cat for testing.

[Tracey1212]

This weekend, I'm going to replace the plugs if I can get those pesky cables off of them. The cables and plugs are original eqpt and the cables seem very stuck to the spark plugs. I may end up destroying the cables in the process and I may replace them as well.
It now appears that the engine is just having a rough idle and that becomes worse at operating temps. While cold, I was able to get steady 3000 rpms, then when it heated up, the best I could get was 1500 rpms, so I feel fairly certain the old plugs and maybe the old wires are at fault.

Thanks to you and anyone else who has ideas on this engine problem. I'm still reading replies and considering every comment strongly.

[maxwedge]

Do the fuel filter also.

[Tracey1212]

I replaced the fuel filter this past weekend and purchased the Champion platinum plugs. Before I replace the plugs and wires, can someone tell me if the engine, a 3.1 v6, rotates forward when you remove the two dog bone supports that connect to the top of the radiator? I need to get to the 3 plugs close to the firewall, and if the engine can be rotated, it will be much easier.

Thanks

[sad-lumina-owner]

Originally Posted by Tracey1212

I replaced the fuel filter this past weekend and purchased the Champion platinum plugs. Before I replace the plugs and wires, can someone tell me if the engine, a 3.1 v6, rotates forward when you remove the two dog bone supports that connect to the top of the radiator? I need to get to the 3 plugs close to the firewall, and if the engine can be rotated, it will be much easier.

Thanks

someone told me you can just jack the engine up from the bottom with a floor jack if you take out the dogbone.

I was so pissed at this that I just pulled the rubber seal off the hood/firewall and sawed out three holes with my jigsaw. Then I used an extension and a socket wrench. I never have to move the engine again to change 3 spark plugs.

You can make a plastic cover and/or hotglue something over the 3 slots.

I just made 6 cuts and bashed the metal back with a hammer.

[maxwedge]

Wow, what is so hard about rocking the engine forward and using the hole in the dogbone mt bracket to hold it? Or blocking the engine using a 2x4 at the rear of the engine to the firewall. BTW, stay with AC plats on this engine.