New sound

I have a 99 gt with 83,000 miles. Recently noticed a new sound when I accelerate. Sounds sort of like a light engine knock, but it does not happen when I rev up in neutral. I love this car and wan to keep it running as long as possible. Also wanted to know if anyone can let me know where to find a tool to rotate the engine so I can change the spark plugs. auto parts store said "tie it to a tree and put it in reverse." Not gonna happen.
Thanks for any help.

You sure it is not detonation from poor quality gasoline?

You do not need to rotate the engine to get to the rear bank plugs. :grinno: Just use the right tools and have patience. If you do that then you may get more knocking sounds caused by damaging the two lower engine/tranny mounts. Plus you will add more total labor time to the job. Once you undo the two front wishbone engine mounts the engine will drop forward with no problems. Getting the engine back into the right position to reconnect the two wishbone mounts will be more of an issue.

I'm getting the same gas as always. I 'll try a new gas station to see if that helps. As far as the engine I'll try to get back there without anything, but in the chilton manual it says you can use a turnbuckle to get an extra inch or two. Thanks for the reply.

If you want to follow the Chiltons then be my guest but you can do the job. Just take your time and have patience. Many of us have replaced the rear bank spark plugs without going through all the hassle of messing with the motor mounts. I do mine in my GTP every year although it is a PITA of a job. The biggest issue you will have is removing the spark plug boots and not damaging the metal heat shields.

I agree with Bob. There are cars that rotating the engine forward is the only way to get to the rear bank plugs, but your car is not one of them. A flex head ratchet, 3" and 6" wobble extensions and a bit of patience is all that are required. I have a set of long handled bent needle nose that help grip the old boots to get them off, but don't use them if you plan on reusing the wires as they will most likely tear the boots.

I was able to get the rear bank of plugs and wires off. I have big hands and arms. Just take your time as stated above. Also be very careful when putting in the new plugs. What I did is put them in by hand with the spark plug socket and a small stubby extension to get plug number 6 in. That is a very tight location. The O2 sensor is also in that location, a very tight location. That was a hard one and also plug 4 was also a hard one it has the black engine bracket there. Just my 2 cents worth. Remember to put dielectric grease on the spark plug boots.

I got the spark plugs changed without moving the engine. Noise still apparent. Sounds more of a rattling though not a knock. (sorry for the bad description). Still can't really tell where the sound is coming from.

The rattling could be from the exhaust system like heat shields, harmonic balancer at the front of the crankshaft, any pulleys in the serpentine drive belt system, A/C clutch, or even a torque converter flex plate so it is important to try to isolate the specific location of the noise although it is not easy to do at times.