Hey guys n' gals!
My baby is having a problem that neither I, nor the dealership can figure out. When I'm at speed, between 80kmph and 120 kmph (that's 50mph - 80 mph for the Americans here), I hear a 'tick' every half kilometer. When it ticks, I can feel the truck lurch, and I can watch the tach drop 200 rpm. I'll be taking her to the shop for the 3rd time in 2 months to have it looked at.
I don't drive her hard, but I'm no softie either. Unfortunately, my 9 to 5, monday to friday job keeps me from attending anything exciting, other than rush hour traffic through construction clogged streets. And just a few weeks ago, I took the truck in for it's annual check as well as routine maintenance.
Any ideas?

 

You couldn't come up with something easier, like what's the air pressure supposed to be in my spare tire...lol

Is this consistant at every 1/2 Kilometer and do you hear the "click" from a certain area? Dash, Engine compartment, rear?
What year is it, 2wd, 4wd, milage, did this start suddenly or gradually and is it getting worse or still about the same as it was 2 months ago. Any codes?
Has the mechanic experienced the problem but just not located it?
Supply as much info as you can and we'll put our heads together and maybe come up with something.

 

No no, I got the spare tire pressure issue worked out a while ago.

The tick just came up about a month ago while hauling my team to paintball. It certainly sounds like it's coming from the engine compartment and not the dash or rear. It ticks regularly at around .5 km. It doesn't do it while idling at the light, nor does it tick when I'm accelerating.

I've taken it to the dealership and they cannot replicate the problem, nor have they heard of anything like this. I'm not exactly sure what you mean by codes.

I have an '05, 2 door, 4x4. I put a K&N filter in a few months ago, but I highly doubt that would be the culprit of my ticking...
I'm just throwing this out there, but could it be the fuel pump or injectors? Kenigan isn't mechanically savvy...

 

actually you know what......i have the same ticking!!! i forgot about it totally (louder exhaust/intake, and a loud sound system)

try turning off you a/c and all your accessories and see if it still does it--i was pretty sure it was some sort of cycling switch but i never did anything about it...

 

not something in the wheels?? that's where I would check first

 

Kennigan,

If reading your post correctly, you notice the tick noise then the RPM's drop 200rpm's. That would indicate a torque management issue with the electronic transmission. I am puzzled as to why the dealer is not picking this up. Clearly you are at cruising speed when this happens, the torque converter has an electronic lock-up mechanism, this engages as the Blazer is at cruising speed. If the converter can not lock up it will continue to make attempts until it does.

Sounds like the dealer needs some more training or at least his service writer.

 

Since you say it does it regularly at .5 KPH it is not your torque converter trying to "lock up". But your dealer's service writer already knows that so don't tell him you think that is what it is because you will look stupid.

 

I'm thinking coils and plug wires from the feel, but can't think of anything to fit the sound. Can only fit the sound with the air conditioning. I don't suppose the compressor switch is kicking itself on?

 

Check to make sure your spark plugs are in tight.

 

Forgive me, but would the A/C unit be on if I didn't have anything working? No accessories, no radio, no A/C...