Maybe someone can help direct me with my troubles.

Symptoms:
1. Rough idling
2. While cruising at about 45 mph, I can feel the engine hesitate (behaves sluggishly)
3. Fuel economy dropped

Current condition:
'05 Limited, manual drive
29,300 miles
Last oil, oil filter, and air filter change conducted at 25,000 miles
Environment: Hot and Humid; 90 deg F and 75% humidity

Corrective actions:
1. Tire pressure corrected
2. Verified air filter was clean and clear
3. Burned all gasoline and replaced with Shell premium (had been using premium, action taken to eliminate the bad gas theory)
4. Reset throttle wire
5. Cleaned fuel system and fuel throttle body
6. Said a prayer for enlightenment

Mechanic doesn't know what the trouble may be. Any advice before I lose my wallet at the dealership?
Also, do you recommend extending the powertrain warranty for $150? What is it really worth? It will only cover the transmission and internal mechanisms of engine (i.e. piston, but not seals)

 

Maybe clogged fuel filter?

 

bad O2 sensor?

 

Bad maf sensor or clogged egr valve?

 

Lets start with the easy stuff. Take the battery to some place and have it tested. Newer cars are really picky about the battery's and do strange things when they are close to failing, but not yet dead. Checks out? Get a pressure gauge and check the fuel pressure. It's OK. Rats, its electrical. Look for trouble codes. None? Rats again. I say goodbye to my money.

The last time something like this happened to me it was the battery, and it didn't give any sighs of being weak.

Could you have 1 bad plug or coil pack? Kinda sounds like a cylinder is not right with the rough idle and bad fuel economy.

Les

 

could also be something simple like a failing spark plug/lead

Steve

lol im now a forum regular!!!!

 

Mechanic said that all cylinders are firering.
No engine service light comes on.

All of your ideas are great. It may be the O2 sensor. It could be the fuel filter too. Maybe one of the 12 spark plugs aren't firering properly. Let me add, the symptoms are hard to notice while driving, but you can sense them. The hesitation is irregular; it’s not predictable or consistent.

What do you think of the warrenty?

 

I'm personally a big fan of OBDKEY or another OBD 2 datalogging diagnostic tool for this kind of problem.

You can record the values of your sensors in real time. It helps when your problem occurs occasionally.

 

Sounds like an electronic issue. I would as one poster said get some tool to log the data and drive around while it's happening. More data means better diagnosis.

 

Yes, especially when you consider the alternative.

Having a dealership diagnose this problem...

Having a ham-fisted repair shop diagnose this problem...

My experience says you will end up with the car in worse shape than it is now...

I believe Crossfireforum.org members get a discount on obdkey.com...

Once you datalog your sensor outputs, then the rest of the forum users can help you with finding your problem.

 

Isn't there a trouble code available? Thought diagnosis was done with a little computer plugged into your dashboard somewhere now days.

 

I'm going to say the Mass Airflow Sensor. I just had to order one for mine as well, about $175. Mine idles fine and throws no code but drives sluggish and hesitates under throttle going with traffic. Cleaning it would fix it for a week or so then it would act up again. It's a very very common problem with these motors.

 

As far as the rough idle, I'm thinking EGR valve or possible vacuum leak. I'm not sure what to make of the cruising speed problem though.

 

If there's no "check engine light" it may be your previous tank of gas was contaminated with water. A bottle
of HEET dry gas will mix with the water which is sitting on the bottom of your tank and will be burned in the engine as normal. It just happened on my BMW bike and its slowly clearing up.

 

Had the same problem with my 2004 Nissan Xterra. Fuel economy dropped to about 8 mpg & I could not get it up to 65 mph (where 85 was never a problem before). Suggestions from "Ask the Expert" started with clogged fuel filter, to bad fuel pump, to possible exhaust leak. I traded it in for my 2005 Crossfire!!!!

 

NEW DEVELOPMENT

Alternator is whining and can be heard over the volume of sound produced from the engine when raising the RPMs.

Any ideas?

 

I agree with the posts above: MAF, MAF, MAF. It's common & explains all the problems you listed.
http://www.benzworld.org/forums/w163...placement.html
Probably wouldn't hurt to pour a can of injector cleaner in the ole gas tank just to make sure it's not a dirty injector. It's cheap compared to a sensor replacement & it's worth a shot!
The alternator racket is probably bearing related. The best way to tell (& this has been mentioned here before) is to take a long handled screwdriver & place it on the alternator body while the car is running. The screwdriver acts like a stethoscope, you'll be able to hear every squeak & rattle. Place the handle of the screwdriver in your ear & make darn sure you don't have anything loose fitting that can get caught in anything!!! If the alternator sounds reasonably quiet then the noise is coming from somewhere else.

 

hi, i've Obdkey software bluetooth.
I've a code error P0410-Secondary Air Injection System Malfunction
What's the problem for you?
The car go very well, but what's code error P0410?
thanks!

 

Mexico63, the P0410 code is the secondary air injection system. That is the pump that is located right on the front of your engine between the air pump switch over valves. See pic attached. Do a search on P0410 error and you will get all of the inputs on what could be wrong.

MikeR

 

Whining alternator turned out to be an idle pulley. Cost <$300 to repair and man was it worth in.