QuestionBuick runs fine when cold but after it warms up the LT1 with 150K acts like we got some bad gas.
I have replaced the fuel filter and added some octain boost and injector cleaner and better fuel and run most of the tank. Still have the same problem.I have had the car for the last 20K miles and the only history that I know is last summer we replaced the tramission and water pump (we did not get the engen hot)
Thanks Randy
AnswerHello Randy,
There is an EGR valve on the engine that operates at certain conditions, but only operates after the engine is warm.
A common problem is on engines with some age on them, pieces of carbon will break loose, and pass out the exhaust.
If the EGR valve is operating at that time, a small piece can get cought under the seat of the valve, and keep it from closing completely, thus forming a vacuum leak condition until it opens again, and hopefully blows it on out.
The egr valve is supposed to be removed and cleaned occasionally anyway, but that won't keep carbon from doing the same thing, even on the first trip after cleaning it.
There is a product called Sea Foam that deserves to be investigated, in case you would want to do that, although I haven't used it.
I have used water before to knock carbon loose and out. See here:
http://www.automotiveforums.com/vbulletin/showthread.php?t=283211
You can Google search for Sea Foam.
Cleaning the MAF sensor is another possibility that might be related to your symptoms. See here:
http://www.fordscorpio.co.uk/cleanmaf.htm
That is a Ford link, but as good as I have seen for that, and they work the same.
Van
