Engine Performance problem
1997 Ford F150 V8 Four Wheel Drive Automatic 175000 miles
I have a '97 F150 with 4.6 V8, automatic transmission, 4x4. The truck was not used for approximately 1 year prior to me purchasing it. When I first purchased the truck it had a slight spark knock during acceleration, slight miss that seamed to clear up and would die when you came to a stop after driving when it was at operating temperature, unless the AC was on. But it was drivable.
Then it would sometimes exhibit a no start condition until it was cranked for several minutes. When it did start it would run really rough, like it had a miss fire or vacuum leak, but would clear up and run okay.
Now it runs rough anytime you start it up, seams like a bad misfire. It can be driven, however you can not accelerate fast or it sounds like it has major spark knock. I have replaced the sparkplugs with autolite platinums, new plug wires, removed the throttle body and spacer and cleaned the carbon deposits from them. Also cleaned the IAC. Also during the whole ordeal there has been no check engine light.
I have read many threads that point at a large range of possibilities but all of the threads have noted a CEL was on. As I have pointed out, I have no CEL on. This could be due to the truck not being driven for very many miles. Trying to avoid the high cost of taking to the dealer, but I am at my wits end for what the cause could be. Any help would be greatly appreciated.
Thursday, January 29th, 2009 AT 7:10 PM