Hello all,

This is my first time posting here because I am desperate for help at this point. Over the past 6 or so months, my dad (who has been a mechanic for almost 45 years) and I have been racking our brains around what could be wrong with my car. We have done a ton of diagnosis and have replaced certain parts that would help. Below are the symptoms that I am having. My questions is: Could this be caused by a stretched timing chain or the timing skipping a couple teeth?

• P0300 random misfire code
• Car will "jerk" as I am cruising down the road
  • Happens the most at 40mph
  • RPMs go up and down the whole time
  • Gets really bad when trying to go up slight inclines/driving in the mountains
• Does NOT happen while using cruise control on the freeway at 65-75 mph.
• Sometimes it will die when I park my car
  • inconsistent as to when it happens

Some of the things we have done (I know that some of these do not have to do with the engine specifically, but you all might be able to see something I don't):

• Replaced all the sparkplugs
• Recently replaced the started
• Replaced the intake manifold due to other problems
• Replaced the AC compressor since it went out.
• New valve cover gasket

 

Do you have a scan tool showing live data?

 

Yes. I have a couple different ones. Is there something specific I should be looking for?

 

I would be looking at fuel pressure, MAF sensor, cam & crank sensors. See if you can pinpoint what readings are going crazy/out of spec when the vehicle misbehaves.

 

If the timing chain "skipped teeth" it would have done it again and wouldn't be running.

 

That makes sense. It seemed obvious to me but at this point, I am willing to think anything is possible.

 

So I tried to see if my scanner could do that, but I have a very basic one that could not do those functions. We thoroughly tested the cam sensor and it seems to be functioning correctly. We recently adjusted the crank sensor and it did not seem to help. It is really hard to tell if it helped or not.

 

If the timing chain did skip a tooth, I would expect a cam/crank sensor correlation code, plus a cam timing code.