ShakeyB

I changed my Cap, Rotor, Wires, and Plugs about 1,500 miles ago. At first I was getting 17-18 MPGs. Now Im averaging low 14s. I went to start it this morning and it had a very rough idle. It warmed up and everything purred again. I am wondering the possibles causes of such an extreme drop if mileage. My gut is telling me that it may be an O2 sensor. It is obviously running on all 6 cylinders, at least I think I would notice if it wasn't. Am I dealing with an ignition problem? Are there any diagnostics I can do to narrow this down? I don't have money to throw at maybes. It's an ODB1. I am assuming that it won't throw a code for an O2 sensor, am I correct? If it is a sensor, which is it most likely to be, because I haven't gotten under it to count them and see their locations yet. Could it be something else entirely?
95 ZJ with 91,000 miles.
Thanks for your help.
Also, I will probably need to hit the JY for the parts. Are the 96 and up sensors different than my 95?
I need my mileage back because I lost my job two weeks ago and I obviously need to spend less at the pump.
Thanks Again

ShakeyB

I had to argue with the NAPA guy about a 95 not having two O2 sensors...lol
I ordered the correct NGK from Autozone and my mileage is back up to 17.5 MPG.
Problem fixed. In my research I learned that Bosh O2 sensors don't agree with Jeeps, the manager at Autozone heard the same thing. NGK is an OEM replacement. All is good until I broke the fuel filter fitting on the line that comes from the gas tank. I posted a thread on that one too, but just like this one, I got zero replies. I guess I'm saying something the wrong way?

jon-d

same reply as the other thread, for myself I did not have any information to offer that I thought would be helpful.


but your follow up post on Bosh is interesting. I always thought bosh is a good brand to use. the Autozone people BTW are not always the mechanical pro's people think they should be. several years ago a buddy of mine worked there and a co-worker stated to him that she was there to learn about cars. he often heard her dispensing bad advice. good for her that she wanted to learn but not so good for the customer that looked to her as an expert.

Fred/N0AZZ

You can find that any place where you walk-in or speak with on the phone, even wrong part # posted on placed like RockAuto. If you go in somewhere it only takes me a min. or two to figure out if the person knows anything or not, same for phone.