ken.norwich

Lately my truck has been shuddering worse than usual. at first i thought it was a ball joint (i had two bad ones) but upon replacing all 4 it seems to just be getting worse. i drive mainly to school and back which is around 30 miles thruway one way. i am leaning towards a tranny but not sure. i'm not throwing any codes and it recently just passed inspection. previous owner had tranny flushed around 35k and it now has 75k. the tranny pan has started leaking and when i got it inspected yesterday they said the tailhouse seal on the tranny is just seeping but will get worse. the shudder in my truck seems to occur randomly when i am stopped at a light as well as when i set the cruise on the thruway doing about 60 it will be running fine then it will just start shaking(everything in my truck rattles all the change in the ashtray my drinks the wheel. i look in the mirrors they are shaking.) today it was pretty bad it started to shudder when constantly accelerating and i gave it more gas and it went a way momentarily but it felt like it wanted to stall shaking worse than ever. does this sound like a tranny problem? there is no odd noises that i can hear inside or outside the truck all cylinders are firing strong no sign of a misfire. i wanna take it to a tranny shop and get there opinion but i wanna have some idea of what i'm talking about when i go in there. any help from anyone is greatly appreciated. 1997 4.2L w/ 75k miles. not sure of tranny i can check if someone knows how to identify it.

skymanr

are you sure all cylinders are firing? It sounds like a couple coil-over packs are out. That's how my truck was acting and eventually the check engine light came on and told me a couple packs were out. Ran smooth after that!

ken.norwich

i dont think its that i'm not throwing any codes and this has been going on for a while now. i put new plug wires on it i suppose i could check the spark at the plugs. but i dont wanna just go throwing out 100 more dollars at a guess ya know

harley9703

what year?

Change all your coils, you'll wonder why you never did!

j.low

If your rear brakes are drum, check for distorted drums. Fixing those solve my problem.

ken.norwich

97 4.2L it is still the original coil pack but i'm not throwing codes and would think if that was occasionally missing wouldn't it throw a code?

97green4x4

Good day,

I'm sure a constant shudder would throw a code fairly quickly!! I have a cylinder #6 misfire and it threw a code after five minutes of constant run time... A shudder that won't throw a code could be a few things, but I am leaning towards fuel related; or lack of good fuel pressure... Clogged fuel filter or weak fuel pump... The next on my list would be to clean the MAFS...

Good luck and please let us know what fixes it!!

Cheers!!

harley9703

Don't quote me on it since the older style coils, wires, are very different from the 99+. But your computer has to misfire on that cylinder consecutively 3 times in order for it to throw a code. With that being said my truck had a horrible stutter, shake, cutout, whatever you want to call it for 2 years with out a code being thrown!

But I would start cheap

1 fuel filter
2 spark plugs
3 clean maf
4 wires
5 coil pack

ken.norwich

to anyone who has the 4.2L v6 engine the coil pack solved my shudder issue. if you still are experiencing a shudder pm me haynes has a very good way to test the coil pack with a voltmeter i can explain it to you in detail