I have a '99 ford ranger sport and I'm having engine trouble. The problem is that my my engine shakes really bad when I accelerate. It's almost like it mis-fires but my 'check engine' light hasn't been on. I have gotten a tune up and

not much to go on. does the truck have any flickering electrical issues? what did you replace on the tune up? and newer vehicles really don't get tuned up because the computers keep it tuned. did anything you replaced make any differences at all? did you test your alternator? when does this happen... just on idle or when under load? <<< lol i have sleepy eyes ... cant read

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Don't spend good money fixing phantom problems. Test, diagnose, and buy the right part(s) to fix the right problem. Read & learn here
http://www.aa1car.com/index_alphabetical.htm
http://easyautodiagnostics.com/main_...articles_1.php
check that sensor BEFORE replacing
http://www.aa1car.com/library/2002/cm70248.htm

I'm having the same sort of issue. Got a 1997 Ranger 4.0 V6. About a year ago I noticed a violent "shaking". Obviously a misfire of some sort. Had several codes like O2 sensor, MAF sensor, vacuum leak..... I started with the MAF, but it did no good other than to clear that code. Then a mechanic friend suggested the coil pack.....and it was a miracle! The truck ran great, and no shaking. 10 months later it came back, so I replaced the coil pack again because it had a lifetime warranty. It ran great for 36 hours, and the hesitation was back. Now I'm not sure what to do, I don't have a ton of cash to throw at "maybe" fixes.
Basically it runs great at idle, but about 3rd-5th gear and 25% throttle, it shakes and hesitates so bad I can barely make it up a hill. Also, the problem comes and goes. It presents itself about 80% of the time, but rarely with a cold engine.

you can try at the bottom of my sig is a link for a site for sensors, how to test and trouble shoot, with a break down of what they do and then in depth links to more tests. see if you can find the right sensor that is giving you fits

__________________
Don't spend good money fixing phantom problems. Test, diagnose, and buy the right part(s) to fix the right problem. Read & learn here
http://www.aa1car.com/index_alphabetical.htm
http://easyautodiagnostics.com/main_...articles_1.php
check that sensor BEFORE replacing
http://www.aa1car.com/library/2002/cm70248.htm

So I've noticed that the shaking in my truck isn't coming from the engine, the shaking feels like its in the middle of my truck. Took to a mechanic and says it could be something wrong with transmission, forgot the name of it but mechanic says its something that isn't locking up right. . It's shifts good though.. Any suggestions?????