IdeaMan
NAXJA Forum User
- Location
- Fresno, CA
If I run 87 octane gas, I get pinging with the AC on or going up a hill. Anything that loads the engine makes it ping on 87. 89 or 91 it runs fine, regardless of the brand of gas. We're talking about the 4.0 6 cylinder on a 97 Cherokee with 160k miles on it. I've been told the timing could be off but that when the vehicle is smogged in California, they check that and it has to be on. (and I just had it smogged) What other issues could be the cause of my pinging problem? I'd like to be able to run the cheaper gas since this thing only gets 14-15 mpg in mixed city/highway driving anyway.