MY HUMMER ENGINES SHAKES LIKE IT WANTS TO STALL ON ME, AND DIDN'T HAVE MUCH FORCE TO PICK UP SPEED WHEN DRIVING. I WAS TOLD BY AUTO PARTS STORE, WHICH HOOKED UP MACHINE, TO CHANGE THE AIR FILTER, SPARK PLUGS, AND SPARK PLUG WIRES. NOW IT DOES PICKS UP FORCE WHEN DRIVEN, BUT ENGINE STILL SHAKES. WHAT ELSE CAN IT BE OR WHAT ELSE DO I HAVE TO REPLACE. I WAS TOLD BY DEALER, I JUST HAVE POWER TRAIN WARRANTY WHICH IS DUE TO END IN 2 MORE MONTHS.
It is possible that the engine mounts are bad. Test them by doing the following; Put the parking brake on
Open the hood and get a line of sight so you can see engine movement.
Rev the engine in neautral and see if it moves more than an inch or so and if you can see the shaking
Then put the vehicle in gear and give it a quick blip of gas
If the engine moves more than an inch or so and maybe even makes a noise when it returns to rest, you need to replace the motor mounts.
You must replace all mounts, inlcuding the tranmission mounts, as a set as a failed mounts when replaced will put more of a load on your older mounts and cause them to fail quickly, so you have to replace them all. You can get stock or aftermarket polyeurathane. The aftermarket ones will last longer but you will feel more of the engines normal vibration. One benefit is that the eninge does not move as much as stock mounts and that travel that is allowed by stock mounts wil be translated into forward motion by afternmarket mounts because the engine will not move so far and start turning the driveshaft sooner.
A few good brans are; Hasport mounts, Innovative motor mounts, these are comlpete high end mounts. Some cheaper mounts or sometimes you can find mount inserts made by Prothane or Energy Suspension. If you need a source to buy them through there is a site called, www. Carrepairlinks. Com that has reputable retailers and you can get discounts by using their links.