Occasional Miss and Hesitation - Ticking me off!

[alex_and_sean]

Well I am posting up again since I still have not fixed this problem. I originally posted this under "rough idle". The idle problem seems fixed but I still have a slight hesitation/miss occasionally. It only happens when the engine is warm.

 

Here is what we have done so far:

1. New plugs

2. New plug wires

3. New fuel filter

4. New fuel injectors

5. New MAP sensor (thanks Brett)

6. New EGR valve (thanks again Brett)

7. New fuel regulator

8. New oxygen sensor

9. New fuel pump ballast resistor

10. New airfilter

11. Reworked and fixed vacuum system

12. Cleaned throttle body

13. Installed catalytic converter and new tailpipe (probably not related but some numnut cut out the converter and replaced with a piece of pipe)

 

After all this, I still have the dang miss/hesitation under the same conditions: warm engine, moderate throttle. :headpop: :mad:

 

What is left? What else should I try to do? At this point I am thinking it may be a sticky valve, but that is all I have left in my head. If this is what it is, I will probably live with it for awhile and actually enjoy the MJ and do some wheeling and fix it later. :eek:

 

Thanks

Sean

[ComancheKid45]

Any work or replacement done to the CPS?

[alex_and_sean]

I have not done anything on the CPS. Based on what I have read, I would think that I would have troubles starting/running and not a miss/hesitation if the CPS was bad. Maybe I am wrong. I have replaced nearly everything else, I suppose changing this won't be too big of a deal. :roll:

[Pete M]

IAC? TPS?

[chicofuentes0224]

Replace the braided ground line at the back of the engine and run a second ground from your negative battery post to the fender.