Joah

I figure this might be the best place to ask this question, as the engine I have placed in my 94 zj is from a 1996 xj. It is somewhat modified. I notice that the engine shakes during acceleration when I first start it in the morning. This will last about 10 minutes and then the shake goes away. Any advice would be much appreciated.

Joah,

Joah

Mayb I will post a couple pictures. I know this is a difficult problem to resolve. I guess mayb I should start by determining if all 6 cylinders are firing at start up. I think there's a tool that can help with this. A plug tester?

dave1123

You can start by letting it warm up for a minute or 2 before starting out and give it a couple of quick shots with the throttle before putting it in gear and you should be able to tell if it's hitting on all 6 or not. It could be you have a lot of carbon buildup from low speed driving that needs to be burnt off the plugs and valves. Take it out on the highway and give it some heavy throttle, like passing gear, a couple of times and see if it gets better. You can also give it a "steam cleaning" as they call it by slowly pouring water down the throttle body when it's hot and running at about 2500 rpm. You can research how to do that on YouTube or on this forum. The jeep 4.0 likes to build up carbon because of the way it's crankcase ventilation works. It bleeds oil vapors into the intake manifold to get burnt in the cylinders and that makes for lots of carbon on the valves and pistons. Let us know how it goes.

Sorry about sounding like I'm talking to a newbie. It looks like you've been around here a while. You probably know everything I just talked about, huh?

Joah

I do know alot but I also don't want to know alot. I always appreciate the helpful response. I am interested in this carbon buildup. I ordered a plug tester it should be in today. I will test to see the firing and then go down the trouble shooting list.

Thanks, have a great day,

97grand4.0

aka the Italian tune up.

Stonehenge8u

First and foremost you are going to unplug your battery cables to your battery for 15 minutes so you can let the computer reset. After you reconnect the battery cables go into the cab put key into the ignition turn the key to engage power to the vehicle do not fully turn on the vehicle. After that when all the lights in your dash go out put your foot to the pedal 4 times do it slowly. Start the vehicle and if you're lucky it should purr like a kitten. Wish you the best of luck