Got an issue with my '06 STR. Whe I go to start it up it will have a rough idle and go up to about 1200 RPM. This only lasts for about 20 seconds then it starts to work it's way back down to 600 RPM and is smooth as ever. From 1200 back down to 600 takes maybe 70-80 seconds. I've also noticed I have a bit of a surge while I'm driving between 40-45 MPH at a steady pace. Not much, maybe 100 RPM, just enough for me to barely feel it. No check engine light.

Would Ethanol make this happen?

 

I doubt it's ethanol. Sounds more likely an air leak or misfire and the PCM is just about coping.

What are the fuel trims at idle & 2500rpm?

 

Not sure what a fuel trim is?

 

Time to read up or seek appropriate help.

 

Really......."Time to read up or seek appropriate help."........I thought I was seeking appropriate help here.............maybe not...........

 

Try google or read existing threads here, better still do both - and stop being lazy. DIY is what it is.

 

Now I remember why I stopped posting here.........LAZY..........how many times have you been to Iraq, Saudi, or Afghanistan?............I’m about as far from lazy as you can get. Next time you reply to a post buddy, think of who you’re posting to………..I’m done with you!!!

 

Absolutely not. Don't believe even 1% of the myths you hear. My non-R will do the stumble thing if I've shuffled it in and out of the drive a few times without going for a proper drive.

The RPM surge at speed sounds like a lockup issue with the torque converter. There's been much discussion on this including some TSBs.

 

Both issues sound related to a intermitient misfiring coil.

Not an expert on the 03+ STR but the idle quality upon start up could also be related to a dirty or malfunctioning idle air control valve. I would point towards the pintle having built up carbon on it affecting idle quality upon start up.

 

The issue might be unmetered air finding its way into the intake system. My suggestions are to...

Remove the plastic engine cover and check the intake clamping areas 1) near mass air flow (MAF) sensor 2) front of silver aluminum oval air intake 3) near firewall, back of silver aluminum oval air intake. The third point has two screws and typically are accessed from the driver's side (US).

If no clamps are loose, next check for intake system leaks/cracks by lightly spraying water around all areas of the air intake system. Start misting just after the MAF sensor (not on the MAF) and slowly make your way to the firewall. If at anytime the engine chugs as you are spraying, you likely have located an air leak.

• Bad tank of gas?
  
  
• Any work recently done in car's engine bay area?

 

Let me google that for you

 

If someone asks in one thread, the information that is returned will come from the people who happen to stumble on that thread at that time, and who feel like answering and is limited to what they feel like writing at the time. And, there is some delay until the various answers come in or more information is gathered.

On the other hand, old threads might already address the problem completely. And, the information from multiple threads can be blended for a more complete understanding of the problem and its solutions. Furthermore, the information can be accessed immediately without waiting for someone to stumble along.

Indeed, if someone is asking a question that has been answered ad nauseum recently, the most knowledgable, qualified and experienced members just might not feel like repeating themselves for the tenth time.

Depending solely on posting a question without further independent research is both risky and inefficient.

It will also get you run out of town on some other boards.

FAQ: What is Spoon Feeding



++

 

Thanks, I'll pull the cover off and take a look at all the lines. I searched for "rough idle" on the site before I posted my question, but it seemed everything I read was about a constant rough idle not a 20 second rough idle. I did find a lot of info on the RP surge at 40-45, but it was all geared towards software updates for the 2003 models. Looks like it might be a possible converter issue since mine is a 2006. Sorry I got ticked off by JagV8. I busted one of my nuckels open while trying to pull the right main landing gear off of a British F-35 (BK-1). I got mad because I saw he was from the UK and here I am banging up hands on one of their jets. Anyway, I've calmed down now. Thanks for the advice.

BTW.....very respectable 1/4 mile time!!!

 

Thanks for the thumbs up on the 1/4 mile time.

I recently installed an upper 2.6" sc pulley and I am looking forward to making some new dyno runs runs as well as some 1/4 mile passes in cool air. Cool air (and better yet, cold air and low humidity) really makes these cars fly. I believe the dyno will prove what I feel and what has been said by others -- most of the power increase is at lower rpms and not much is gained in our high rev range with pulley swaps.

 

People in this forum are mean.

 

No these guys are great. JagV8 is a smart guy with these cars.......I think we just hit each other on a bad day.......

 

It's not a biggie. Stuff happens! Sorry to hear about your knuckles.

 

No- Tony is right, we are mean. My neighbour across the street is an 85 year old widow. After cutting her grass and taking out her trash, I was too tired to finish cleaning the eaves troughs but promised that I will do it tomorrow. I really felt bad and am sure I will burn in hell, but so be it.

 

It's my fault for not wearing gloves. I've been working on aircraft for over 20 years, you'd think I'd know better by now......