1999 Toyota Sienna Jerking Motion

I have a problem with my 1999 Toyota Sienna jerking when I accelerate at higher speeds. About a month ago while on a trip I noticed the van was jerking going up hills. Since then it has gotten progressively worst. My mechanic looked at it and hooked it up to the computer, but no codes showed up. Then he tested the fuel line with a sensor to see if I had gotten some bad gas on the trip. This also checked out as fine. They did a visual inspection and said the spark plug wires looked frayed and charred and they were surprised that the check engine light had not come on yet. He said he could not promise that replacing the plugs and wires would fix my jerking problems, but that it would need to be fixed sometime anyway. I had the plugs, but not the wires replaced at 112,000 and the van is currently at 140,000. Since I had already spent $200 looking for a solution to my jerking problem, I was hesitant to spend another $400 replacing the wires and spark plugs and still not fixing my original problem. (I have 3 children in college next year so we are pretty broke.) He also said I had a ?waste spark? system. Does replacing the spark plugs and wires seem like a probable solution to my jerking problem? Why did the computer not indicate that this is a problem? And is $400 reasonable to replace 6 spark plugs and 3 wires? Right now they say we do not need to replace the 3 ignition coils. Thanks for your help. I enjoy your column and radio show.



Lisa

Cary, NC