Not sure if this is a problem or not but, it's bothering me enough to ask. I have a 96 CE with LT1, 38k miles and automatic trans. When I'm cruising at highway speed and punch it to pass someone, I hear a ticking that almost sounds like pinging. It never does this when taking off from a stop. Also, if I punch it to the floor when it starts ticking, the rpm's jump higher an dthe ticking goes away. So, it only ticks when I gas it enough to downshift and speed up but, not at WOT. I'm running 93 octane consistently so I assume it can't be pinging. No check engine light or any other warning lights and all guages look fine. Any other ideas what may be causing this?

More importantly, is it dangerous at all to drive while it's doing this?

Thanks in advance,

 

Try putting some octane booster in your next fill up and see if the noise goes away. If it does, then its pinging. With only 38K on a 15 year old car you may have some carbon build up on the pistons or heads.

 

First, you really have to define the noise its making...ping is a lite almost tin, rattling that is caused by overheated combustion chambers and carbon build-up. Knocking is a deeper, harder metalic sound that is caused by incomplete combustion or poor combustion caused by bad wires, old plugs, bad gas..etc. Tune up related things. Your engines knock-sensor would make the necessary adjustments to stop any knocking almost as soon as it started, so the noise would not go for more than a split second normally.

Then there is injector tic, that usually can be heard at stop lites, idle but not at speed. Harmless.

Knock from mechanical damage is obvious and more of a rapping against the metal, solid sounding and distinct. You;d know it if you heard it.

Could your sound be described as a spitting noise? that is inconsistant, and only heard under certain conditions, like gassing it under a load or uphill...passing or suddenly applying enough pedal to get it to kick-down a gear?

Could be a small exhaust leak. I've got the same issue right now. I'm just trying to figure out exactly where and what, then why.

if you;re already running good fuel, and it does not seem to be effected by engine temps, pretty much will do it at any temp, then I'd say exhaust leak either back thru the air mngt system, a manifold leak or even a donut at the collector below the heads. Also check the EGR gasket and EGR itself for signs of exhaust leaking. If yours has some EGR plumbing, that too can leak and make t hat annoying spitting or ticking sound.
Make certain all plug wires are tight, and there are no vac hoses pulled off or broken. If the car idles good and actually performs well, thats even more evidence of a leak and not an actual tune issue.
Hope this helps..

 

What's the suggestion on cleaning up the carbon? I have some Lucas Fuel System cleaner that is listed to "clean carbon deposits" but, curious to see what everyone else is doing for this.

I also bought some octane boost last night and will try that on my next fill up.

Thanks,

 

My God, I hate to suggest this because it always gets so much controversial feedback from some individuals, but here goes..."Seafoam" ... If poured into the vacuum hose off the brake booster, then let it sit for about 15 minites, it will remove any and most all the carbon from inside the motor......
Here's another thing you might consider, it could be a exhaust leak. I had a exhaust leak at the exhaust manifold that sounded exactly like ticking..Might want to check it out just in case.....WW

 

spray it with a 50hp shot of nitrous, trust me you will have no more nitrous

 

I vote for "exhaust leak". I do believe these are the source of 90 percent of unknown variable ticking. At least in my experiences.

 

J/k

The car probably just needs to be "driven".

If there are no codes, visable issues/problems and fluids are good/topped off: throw a full can of "seafoam" into the gas tank and run that puppy hard until you use the entire gas tank up. Refill the tank with fresh gas and see if your "ticking on acceleration" is still there.