3rd Gen 4R slight engine vibration during idle
 

Hello,

I've recently been feeling a vibration that seems like it is coming from engine bay. Truck idles at 1200 when started, then rests at about 700 once warm (takes about 10 min). The vibration seems to be present after the truck warms up and idles around the 700-800rpm range. If I turn on heat/fan, the idle jumps to about 850-900 and the vibration goes away. With the foot on brake and truck in Neutral or reverse or even moving slowly, the vibration is still there. Seems like it goes away only at higher rpms..

I checked the engine mounts by looking under hood from driver seat method and they seem ok. I will check trans mount tomorrow. Any other suggestions is greatly appreciated.

Thank you

When was your last tuneup?

Did you run a good injector cleaner lately? Techtron, Gumout, and amsoil are my go to’s.


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It could be your injectors. If the cleaners don't work you can send them to RCFuelinjection.com to check and clean.

Cleaning the maf and testing it for resistance also vacuum leaks could help

The last tune up was about 4 years ago. The plugs and wires still look good. I ran some STA-BIL through early spring 2022 and I remember it dying out at a stop sign. It quickly started back up though. The engine has 225,000. I believe that it needs a new steering rack. I also have a box here full of new plugs, VC gaskets, pcv, etc... all oem and just waiting for the right moment to put on. I just hope that no engine problems are starting.

If you're going to do VCGs then the injectors will be readily accessible

Check the fan clutch before tearing in

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A slight miss may be a loss of compression. While it can get so extreme that it may necessitate replacing I don't think you are anywhere near that. My original engine had 60 PSI and 100 PSI in two of the cylinders (150 in the rest) and it missed pretty bad at idle but ran strong for years. Loss of compression is a normal issue to have as an engine, from any vehicle, starts to rack up the miles.

FWIW, I dump a bottle of Techron into my tank, 2 or 3 times per year. I've been doing this since buying my '01 new. The fuel injectors have never been touched and now have about 519,000 miles on them.
My engine tends to have a hint of a stumble at idle, but nothing that in any way concerns me given the age/mileage. Apart from all of the other maintenance, I replace the air filter (Toyota) & spark plugs (NGK BKR5EKB-11) every 25,000 miles.
I need to put another shopping list together for my 3rd timing belt job coming up soon. :)


Andreas

I now had a similar idle vibration problem. I checked for vacuum hose leaks with smoke - pass, then checked for loose or failing sparkplugs or wires - pass, sprayed the MAS with cleaner - no improvement, added "Heat" to fuel in case water in fuel due to sitting 1.5 yrs - no improvement. Then swapped in a new ignition coil - success! It idles so smooth now it sometimes feels like it's off.

The thing about adding fuel system cleaner into gas tanks to clean out injectors is that it also can clean out particulates trapped in the fuel filter, which then move on into the injectors - so this can make things even worse. The good cleaners do seem to work but I set up a simple mod to feed to cleaner into a fuel hose that connects directly to the fuel rail. With some air pressure, the engine will idle with the cleaner ok. Do this about every 30k.