Im new to the site and need HELP. I have an '02 Ram 1500 with a 3.7. I bought it used about a month ago with around 85000 miles. I began to notice a small misfire or vibration. I immediately changed the oil, plugs, emissons cleaning treatment, a transmisson flush,air filter,and had a computer put on. The computer scan came back clean but the mechanic also noticed the small vibration/misfire. He told me it was probably a bad coil so I bought a coil and switched out each one at a time to no prevail. I took it to another mechanic which his computer read bad O2 sensors readings and recommended I clean them out along with a sensor besides the throttle body. After that , the check engine came on and I still have the misfire/vibration. A few people have told me that the misfire-like vibration is common with these trucks. Any info is greatly appreciated before I start taking guesses again as to what it is.

 

I have the 05 with manual tranny and from the beginning it had a vibration on the stick and rattle like a diesel. Lately, it had a vibration at hwy speeds, but it was fixed with road forcing the tires. Since your truck has 85,000 miles, have you checked your engine mounts?

 

The engine mounts really never crossed my mind but u may have a point. When the truck was revved, the computer scanner would read 0 coming from the oxygen sensor. I can't recall if it was the one before or after the converter. Would this make a difference in the way the truck performs? What would happen if you remove the oxygen sensors completely?

 

If you can find an auto repair shop in your area
that has a SnapOn Vantage meter
with the 'secondary ignition testing module'

http://buy1.snapon.com/products/diag...mp;dir=catalog

it should be able to tell you where the missfire is coming from
or whether all cylinders are firing properly
and the vibration you feel is mechanical.

If it turns out to be mechanical
Chrysler dealerships are supposed to have
the special tool
Special tool OT-38793 "Electronic Vibration Analyzer Kit (EVA)" can be used to help pinpoint surge/vibration issues. The tool provides the frequency and amplitude of the vibration.
described in this TSB:

http://dodgeram.info/tsb/1998/18-49-98.htm

With the info this tool gives
a well trainned Chrysler tech
can pin-point where the vibration is coming from.

 

Check this link, it shows you what and how to test an oxygen sensor.

http://www.wellsmfgcorp.com/pdf/Counterpoint2_3.pdf

 

Would a bad oxygen sensor have any factor in it misfiring? Has anybody completely removed the cat?