I have a 2006 Chevy Colorado 2.8L w/ about 145k miles on it. This morning on my way to work, I was on a street going about 30-40 mph with my foot OFF the gas pedal and the RPMs were pulsing with the truck trying to accelerate with each pulse. It did this for about 50 yards. I noticed it after about 20 yards and when I noticed all this happening, I could also hear a sound outside my passenger-side window that sounded a little like a rattle. My brakes are perfectly fine, but I noticed that when I slowed down, the truck was still trying to do this "pulse thing" and since I was a ways from my turn, I decided to press down on the gas pedal. Once I did that for about 10 or 15 yards, it all stopped and the sound disappeared. Everything back to normal.
I'm not sure what's going on with this but this is the first time this has happened. It scared me a bit.
The last issue I had with this truck was last winter when it had a problem starting. The truck would try to turn over but end in a low screech. It did that for about 10 minutes (I tried to start her about 3-5 times with the final time ending in success.) It was the only time that had happened but I brought her into my local Chevy dealership a couple days after that and the mechanic made it sound like the engine's oil rings might be worn down because they said they couldn't see any oil on the dipstick when they checked it (which is crazy because I'm 100% on top of my oil changes--every 3k miles, always a new filter, no leaks anywhere; I go over the entire engine every time I do my changes and always use 5 quarts like I'm supposed to with SAE 5W-30.) Anyway, the mechanic suggested adding maybe about 1/2 to 1 more quart more when I do my changes, which I've started doing to be 100% safe with oil amount, but he also made it sound like the timing chain could be on the way out and that if I'm not wanting to swap the entire engine, that I should get the chain swapped, which will run me about $2k at a mom-and-pop shop who also quoted me around $7,800 for a new block (minus other componants, but if I go that route, I'm going to save up to about $10k to hopefully get a new starter, a new power-steering pump, and a few other things if possible). I was hoping to hold off until about August to take the truck in to have it looked at a little closer because that would be the time I'd decide on something, but with this morning's issue, I'm worried that I need to take her in as soon as possible now.
Back to this weird revving / noise issue, does that sound like a chain skipped a tooth and that my pressing on the gas got it back in timing or does this sound like a transmission issue? The transmission is getting some age on it (I had it swapped by that mom-and-pop place back at like 90k-something miles or sometime around 2013) but I've not had any issues with it that I can tell. It goes from from park to drive, etc. without any issues. I can't imagine a transmission would make the noise I heard this morning, too, but considering it was acting almost like it was having problems coming out of a gear or something when my foot was off the pedal, well, I can't tell.
I'm not sure what's going on with this but this is the first time this has happened. It scared me a bit.
The last issue I had with this truck was last winter when it had a problem starting. The truck would try to turn over but end in a low screech. It did that for about 10 minutes (I tried to start her about 3-5 times with the final time ending in success.) It was the only time that had happened but I brought her into my local Chevy dealership a couple days after that and the mechanic made it sound like the engine's oil rings might be worn down because they said they couldn't see any oil on the dipstick when they checked it (which is crazy because I'm 100% on top of my oil changes--every 3k miles, always a new filter, no leaks anywhere; I go over the entire engine every time I do my changes and always use 5 quarts like I'm supposed to with SAE 5W-30.) Anyway, the mechanic suggested adding maybe about 1/2 to 1 more quart more when I do my changes, which I've started doing to be 100% safe with oil amount, but he also made it sound like the timing chain could be on the way out and that if I'm not wanting to swap the entire engine, that I should get the chain swapped, which will run me about $2k at a mom-and-pop shop who also quoted me around $7,800 for a new block (minus other componants, but if I go that route, I'm going to save up to about $10k to hopefully get a new starter, a new power-steering pump, and a few other things if possible). I was hoping to hold off until about August to take the truck in to have it looked at a little closer because that would be the time I'd decide on something, but with this morning's issue, I'm worried that I need to take her in as soon as possible now.
Back to this weird revving / noise issue, does that sound like a chain skipped a tooth and that my pressing on the gas got it back in timing or does this sound like a transmission issue? The transmission is getting some age on it (I had it swapped by that mom-and-pop place back at like 90k-something miles or sometime around 2013) but I've not had any issues with it that I can tell. It goes from from park to drive, etc. without any issues. I can't imagine a transmission would make the noise I heard this morning, too, but considering it was acting almost like it was having problems coming out of a gear or something when my foot was off the pedal, well, I can't tell.