Hello everyone, I could really really use some help with my friends cougar. Not 100% sure what is the issue but I’ll explain what is going on. So a couple months ago his vehicle started running really bad. When you first start it, it starts just fine. But as soon as it gets to operating temperature it starts acting like the catalytic converters are plugged. Has really poor acceleration, the engine starts surging, won’t go over 30 mph. If you turn the vehicle off for a few minutes and then start it again it will run fine for a couple minutes, but then it starts with the engine surging, poor acceleration, and won’t get over 30 mph. Also when you come to a stop at a light or something it eventually stalls even if you are trying to give it has. We know it has some vacuum line issues, but haven’t been able to come across a full vacuum diagram for his vehicle. I don’t think that the issue is only within the vacuum lines (vacuum leaks), I think there is something else as well causing these issues. Any help or advice would be greatly appreciated. Also if anyone has a full vacuum line diagram for this vehicle they wouldn’t mind sending this way I would greatly appreciate it too.
i know nothing about these type of cars as not from the US, but you need to make sure the PCV system is sealed up, get every vacuum line you can replaced
i also tend to blame distributors when engines get cranky when hot, check timing and leads, if it’s driven off the cam you can try rotating it when its hot and see if it changes
timing belt stretch?
i assume you’ve checked the basics, are the plugs and leads okay?
Not a familiar at all to the 6cyl… Majority of Cougars around me, were the XR7 / V8s
Did the CC ever get cleaned / changed out?
MAF / Fuel Filter?
Had the throttle body been looked at?
When first running the ecu does not use the o2 sensors, it uses internal fuel maps. Once warmed up the ecu uses the o2 sensors for fuel mapping. The o2 sensors are the only sensors that wear out over time. Lifespan is about 100,000-150,000 kms.
Also, you can use a vacuum gauge to diagnose many engine problems, including clogged cats.