Hello, I'm new to the forum and have a ?? about my 1998 4.2 V6. I purchased the truck 4 years ago with 100,000. The truck now has 151,000 and does not use a drop of oil between oil changes(Valvoline semi-synthetic), makes more power than ever and I'm getting the best gas mileage ever.
At 130,000 miles I replaced the original sparkplugs with AC/Delco Rapidfires.The problem is the truck developed a rough start when cold. After the motor starts it runs perfectly! 5,000 miles later I got a check engine light and a computer code for multiple cylinder misfire. The motor would buck everynow and then on a sight uphill grade at highway speeds, i thought the lock-up torque converter was kicking in and out since the trans. had so many miles. I switched to Bosch platinum plugs and no longer have the bucking misfire but still have the cold start issue.
Now the temp. is near zero here in Iowa and the motor cranks roughly for 6 or seven seconds before starting(but runs great after starting) and never fails to start.
Any ideas or experience with solving this same problem would be greatly appreciated . Thanks, Pete