AntleredRuin
New member
Ok, so I've had my '99 3.4 Automatic for almost a year now, and I've had this problem almost the whole time (I noticed it like 2 days after I bought it. Of course)
I've put almost 18k on it since I bought it and it has not gotten worse. I'm currently at 149k.
I have a very slight 'knock' when at idle. This is the only word I can think of to describe the issue. It does not really sound like a knock at all; it's hardly audible. I can just tell that there is a definite 'whumph' that's timed with engine speed. It's more of a feeling that I can 'hear', as odd as that sounds.
It almost sounds like a wobble, if that makes sense. Like an off balance bowl rolling around until it finally comes to a stop on it's base, but more cushioned than that, faster (with engine speed) and it never stops.
The noise is so quiet that I can barely hear it, much less get it on video to show you guys.
It only does this at idle after warmed up (I'd say after 1100 RPMs it goes away) The truck idles high at a cold startup (as do all cars), so once that high idle is gone, the noise appears. It SEEMS to be more pronounced when the AC compressor kicks on (it kicks off and on a LOT), but I know this changes the RPMs slightly. It is super quiet after this wobble goes away.
The truck drive great and has plenty of power. Idles nice and smooth (in fact, my boss with a 5.7 Sequoia commented on the smoothness). Starts up fine, redlines when floored fine, etc.
I've done a lot of basic maintenance. Spark plugs and wires (NGK/Denso). Fuel filter, plenty of oil changes, complete radiator flush, several tranny drain and fills, replaced the PCV, etc.
I had to replace the FPR a few months after I bought it, and replaced a fuel injector that I broke while doing that. The issue was happening both before and after this job.
When I was doing the FPR/Injector, I opened the valve covers and things were squeaky clean (of course I did not get a picture).
I've not replaced the drive belts, and the T-belt was replaced at 88k before I bought it. Could an improperly tensioned belt cause this noise?
I've heard that the 3.4 has an inherent knock for lot of people that has never been an actual issue. If this is the case, then great, but I'd like to get this taken care of if it could be at all an issue (especially since I've ignored it for almost 20k now)
I've put almost 18k on it since I bought it and it has not gotten worse. I'm currently at 149k.
I have a very slight 'knock' when at idle. This is the only word I can think of to describe the issue. It does not really sound like a knock at all; it's hardly audible. I can just tell that there is a definite 'whumph' that's timed with engine speed. It's more of a feeling that I can 'hear', as odd as that sounds.
It almost sounds like a wobble, if that makes sense. Like an off balance bowl rolling around until it finally comes to a stop on it's base, but more cushioned than that, faster (with engine speed) and it never stops.
The noise is so quiet that I can barely hear it, much less get it on video to show you guys.
It only does this at idle after warmed up (I'd say after 1100 RPMs it goes away) The truck idles high at a cold startup (as do all cars), so once that high idle is gone, the noise appears. It SEEMS to be more pronounced when the AC compressor kicks on (it kicks off and on a LOT), but I know this changes the RPMs slightly. It is super quiet after this wobble goes away.
The truck drive great and has plenty of power. Idles nice and smooth (in fact, my boss with a 5.7 Sequoia commented on the smoothness). Starts up fine, redlines when floored fine, etc.
I've done a lot of basic maintenance. Spark plugs and wires (NGK/Denso). Fuel filter, plenty of oil changes, complete radiator flush, several tranny drain and fills, replaced the PCV, etc.
I had to replace the FPR a few months after I bought it, and replaced a fuel injector that I broke while doing that. The issue was happening both before and after this job.
When I was doing the FPR/Injector, I opened the valve covers and things were squeaky clean (of course I did not get a picture).
I've not replaced the drive belts, and the T-belt was replaced at 88k before I bought it. Could an improperly tensioned belt cause this noise?
I've heard that the 3.4 has an inherent knock for lot of people that has never been an actual issue. If this is the case, then great, but I'd like to get this taken care of if it could be at all an issue (especially since I've ignored it for almost 20k now)
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