Randomly and on cold startup, engine turns over fine with what seems to be short-term misfire upon RPM settling lasting only a few seconds which causes it nearly to stall. Exactly the same as this guy's issue: http://www.youtube.com/watch?feature=player_detailpage&v=rXdU5T7owBk

Once it catches itself, idle stabilizes with no codes being thrown. No evident battery issues or issues driving or at normal idle; again, this is random with it not occurring during the majority of startups.

I have replaced the battery and cleaned the TB/MAF sensor with no real improvement noticed outside of acceleration response; additionally, I have replaced the EVAP solenoid and thermostat. Probably due for some plugs.

I have heard of some talk about some generic batteries being undersized relative to startup diagnostics. I also know there is a prevalent issue with OEM battery terminals which I intend to replace.

Given the randomness, not convinced it is an injector issue. Battery seems to be the primary candidate, especially given the weak OEM connections.

Any guidance or opinions would be greatly appreciated.

Thanks,
John

 

Welcome to HF.

How many miles on it?

How did you clean the TB, looks more like a sticky throttle plate which the PCM is over compensating for on the vid. That usually is upon initial fire up, not repeat starts after up to full operating temp.

Not attempting say you did not do it correctly, but what some people call cleaning the TB is not my version of it???

When you do replace the crappy OEM Battery Terminal Connectors, if that corrects this issue I definitely want you to follow up and let us know. You are way ahead of most people that come here looking for some input as you are aware of some of the common culprits.

 

Hi doc,

Thanks for the reply. I removed the TB and sprayed and scrubbed with cleaner. Amazing how much build up there was with the plate returning to the bronzish sheen. If it is in fact the plate, what would you recommend in terms of cleaning?

The guy in the video indicated his problem was cured when switching to a deep cycle battery. Don't know that is the route I'm going to take, but I am considering going to a red top optima with military spec. connections.

I'm just about to hit 100k miles.

 

Well, you cleaned it properly, so maybe it is a voltage irregularity?

Good luck.

 

Jmac, I had similar symptoms last year on my 2008 with ~59k miles and it turned out to be a crack in the cylinder head. I hope this isn't your case.

 

ANY battery in ok shape will be fine. batt will not cause running problems.
i once put my little lawn tractor batt in my 3.7 h3. it ran just fine.
wouldnt do it in jan at -15 deg!!

the batt just needs to crank it, the gen provides all needed juice when running.
that assumes the batt connectors are good! the batt filters noise like a big capacitor.