Q: I acquired a 1998 Ford Taurus with a 3.0-liter V-6. There are two problems. The first problem is that there is a lot of rust in the cooling system. The cooling system had been flushed before I acquired it but it still seemed rusty so I flushed it again myself. The rust came back so I flushed it a second time, making sure to add the proper antifreeze and a rust preventative. The rust has again returned. Someone said that maybe the heater core or head gaskets are bad. What do you think?

The second problem is that the RPM seems to be idling too high. You get whiplash when you shift into reverse and it feels like the cruise control is on when coasting around 40 mph. Someone said that the Idle Air Control motor might need to be cleaned, or maybe the throttle position sensor is bad. What do you think? -- Dan, Tinley Park

A: Dan, if your Taurus has the pushrod V-6, known as the Vulcan engine, and not the Double-Overhead Cam (DOHC) version, there has been a documented concern regarding cooling system contamination. Technical Service Bulletin (TSB) # 01-11-6 spells out the details of an 82-step procedure, which involves adding a coolant by-pass kit, a new water pump, and using a chemical cleaner as part of a thorough flushing procedure. Stop by your local Ford dealer to see if they’ll provide you with a copy of this TSB. This procedure might be more than you could handle, though. As for the high idle, I don’t think it’s the result of a faulty throttle position sensor. It’s possible that the idle air control valve could be sticking and needs cleaning or replacement. It’s also possible the throttle housing, where the idle air control valve is attached, could need cleaning or repair.

Q: I own a 2001 Dodge Grand Caravan with a 3.3-liter V-6 engine. The problem is that the spark plugs in cylinders 2, 4, and 6 keep fouling out after about 200 miles of driving. The vehicle goes down the street okay, but the idle seems bad. I’ve had it to dealerships and shops about seven times and they can’t’ seem to find the cause of the problem. They’ve tuned it up, replaced the spark plug wires and replaced the intake manifold gasket to no avail. Please help. -- G.R. Niles

A: G.R., you need to find a repair facility that will be patient and determined to get to the root cause. My suggestion would be to look at the Illinois EPA’s Repair Facility Performance Report (http://www.epa.state.il.us/air/vim/rfpr/index.html) to find the shops with the highest success rate at fixing emission related problems. These are shops that likely have trained ASE-certified technicians who will be able to diagnose your vehicle’s problem. Since you mentioned that the idle isn’t very good, the technician should have something to go on. Maybe the front exhaust manifold has a small crack. Cylinders 2, 4, and 6 are up front and if the exhaust manifold is cracked, extra air will be drawn in past the oxygen sensor. This will cause the Powertrain Control Module (PCM) to add more fuel to those cylinders, possibly leading to a misfire. This condition can be easily checked by looking at fuel trim numbers with a diagnostic scan tool. A smoke machine can be utilized to determine if the manifold is cracked.

AutoAdviser: Ira Siegel is an Automotive Instructor and ASE Certified Master Auto Technician. If you have auto-related questions for Ira Siegel you can call and leave your questions at the Auto Adviser Hotline at 708-633-6839 or e-mail a question to Autoadvisr@aol.com.