On my 1997 XK8 the engine started shaking like crazy at idle. Not running good even at higher RPM's. It started after washing the car and engine. Maybe just a coincident. Anyway i thought maybe the computer got wet but it was all dry. I took all the the connectors off and cleaned them with electronic cleaner but no change. The computer shows no error codes. No check engine light. Any ideas???

 

I remember when I worked at the dealer and the flatbed tow trucks would drop off cars when the owners washed the engines. Thanks for the memories.

bob

P.S. Don't get electronics in the engine compartment wet. Bad things happen.

 

Thanks... Im glad to amuse you but what am i looking for to fix this?

 

BTW it started shaking about 4 days after the wash.

 

Look at fuel trims, mainly LTFTs.

 

I dont understand how to to do that. Please.. i need instructions

 

If you washed the engine, there is a good chance some water got down into the spark plug holes in the valve cover gasket. Each plug has it's own tube/cylinder it fits down into, with a coil pack on top. Water can pool down around the plug and cause misfires.

Plenty of you-tube videos out there, always check the easy fixes first.

 

For fuel trims, get an ELM327 Bluetooth OBDII scanner unit (Amazon, ebay, etc. if you don't have one already) and plug it into the diagnostics connector under the dash by the driver's door. Install Torque Pro app on a cell phone and pair (bluetooth) with the scanner. In Torque Pro, select realtime information and swipe right until you have a blank or near blank page. Touch and hold in a blank part of the screen until "add display" appears and press it. Select Digital display and scroll through the display items until you find Fuel Trim Bank 1 Long Term and select it to add it as a display. Repeat to add Long Term Bank 2 and short term bank 1 and bank 2 displays. Also add an Engine RPM display. You now have a real time Fuel Trim measurement page in Torque Pro (this may also work in the free version of Torque but I've never tried that).
Search "fuel trims" in this forum and you should come across a link for a nice tutorial explaining short and long term fuel trims as well as several threads which will give you an idea of what measurements you should see at idle and at 2500rpm.

 

Well guys.. I can't feel more stupid. Removed the drivers side cover to the coils and plugs and lots of water. Removed the coils and plugs, cleaned everything out and wiped it all down with WD40. Started up and runs as new. The cover was replaced with a new one but maybe it was not screwed down tight enough.
Thanks again for all the help.

 

Good enough!