Engine Mechanical problem
2002 Dodge Dakota V8 Four Wheel Drive Automatic 105000 miles
I have a 2002 dodge Dakota 4.7 V8, 4 Door, 4 wheel drive. It has 100,000 miles. It has never had any significant mechanical issues. About 2 weeks ago, it started idling very erratically. It would should up to close to 2000 RPMs at startup, then fluctuate between about 700 and 1300. At a red light, it would shoot up again and cause the truck to lurch forward. I took a video of what it is doing. Here is the link.
This is parked in my driveway after a 20 minute drive. Reading and speaking with a friend, I guessed it could possibly be the Idle air controller. My friend told me to :
"To clean the throttle body and idle control valve, they need to be removed and once on the bench, a good blast of throttle body cleaner in both will hopefully clean them out. Really saturate them to break up the carbon, I'd guess using a whole can of cleaner is not out of line. Compressed air to blow out any residue and carbon solids is helpful but not necessary if you were to put some elbow grease into them. Once they have been cleaned, let them sit so the throttle body cleaner can evaporate before reinstalling. This could take a while.
Well, I almost did that. I was slammed for time, and I have really only worked on carbureted vehicles. I called the Valvoline oil change place and asked if their fuel system cleaning cleaned the Idle air controller. They said it did. I figured paying $60 was worth having someone who knew what they were doing take care of it. It wasn't that thorough of a cleaning. He removed the square black plastic cover on the top of the engine. That led to what I believe is the throttle body. He dipped a stick with a cloth ball on the end into some cleaning solution and swabbed that around in the now exposed metal pipe. I'm calling it a pipe. It had 2 devices coming off the side. One the size of a salt shaker and one maybe half the size of a salt shaker. I believe one of these is the idle air controller. He then poured a fuel system cleaner in the tank and hooked up an 'IV bag with tubes' to the engine. I couldn't see exactly where, because I was pumping the gas when requested. He was flushing a fluid through somewhere and it was causing a ton of white smoke to come out the exhaust. Once they were done, I was thrilled. It seemed fixed. The problem which had occurred constantly was definitely gone. They asked me to go ahead and fill up on gas. I did. As I got down to about 1/4 tank, the problem started to come back. I have since had to fill up again, and the problem is definitely back. The video posted above was from yesterday. It is as bad as ever.
Any ideas? I am short on money right now, and would really like to avoid a trip to the mechanic if possible. I worked on all our car issues (and small engines) with my dad when I was a kid in the 80s and early 90s. I just haven't done a lot of work on more modern cars. What do you think? Should I try a more thorough cleaning of the idle air controller? Do you think that is what it is? Any ideas why the initial cleaning would appear to completely fix it, and then the problem came back within 2 weeks?
Saturday, July 10th, 2010 AT 1:34 PM