Real crappy mileage, NOOB question

[gatormike69]

Just picked up 1996 Camaro for the wife. It runs ok but really gets crappy mileage.......... maybe 10 mpg around town. The kid I bought it from had just replaced the muffler and dual exhaust out the back, but it also looks like he took out the cat conv and I am wondering if by doing this he confused the computer and the rear O2 sensor is giving information that is making the system use a lot more gas than normal. The car has 98K miles but I was told the motor was swapped out a couple months ago, so no telling how many miles on the 3.8. Should I try and get a cat installed or is there another way around the issue. I have yet to decode the flashing then steady service engine light. Thanks for any help y'all might be able to provide. If this has been covered please point me in the right direction. thanks

[vr4gasm]

Re: Real crappy mileage, NOOB question

post cat o2 has nothing to do with MPG...

[gatormike69]

Re: Real crappy mileage, NOOB question

Thanks for the prompt reply. I have no problem with my 58 Apache with the 350 or the old VW, but having a computer interface with the motor is totally new for me. So, I will keep reading these great forums and get this 3.8 running a little more efficiently soon. Thanks again. :tup:

[vr4gasm]

Re: Real crappy mileage, NOOB question

just so you know the post cat o2 is just to tell if the cat is there or clogged... if you want better mileage i would say put the cat back on and get a k an n filter

[Meatyshells]

Re: Real crappy mileage, NOOB question

just so you know the post cat o2 is just to tell if the cat is there or clogged... if you want better mileage i would say put the cat back on and get a k an n filter

putting a cat on the car and swapping in a high flow air filter isnt going to help his problem of 10mpg.

My guess is that your primary o2 sensors, you have 2 of them (1 in each header) are old. Mine went out and were causing the car to think it was running lean, thus adding more fuel. Replace your o2 sensors

[bigbrian442]

Re: Real crappy mileage, NOOB question

The flashing SES light generally means the engine is missing. General tune up and checking the coil packs would be in order.

[nascar24jd]

Re: Real crappy mileage, NOOB question

You should start with the SES light as mentioned above. If it is flashing and then steady then you certainly have a problem. Get it scanned and see what comes up.

[Teal3800]

Re: Real crappy mileage, NOOB question

It could also be a bad wire or plug so I'd recommend changing them that too. It's happened to me quite a few times, wire gets to close to headers, etc.

[RadRacer]

Re: Real crappy mileage, NOOB question

The flashing SES light generally means the engine is missing. General tune up and checking the coil packs would be in order.

^^^^
What he said; I'm surprised the first posts didn't pick that up. AutoZone, Advanced Auto and most local auto part stores will scan it for free; the dealer will charge like $45 or something. Once you get a code, we can trouble shoot it alot more effectively instead of wasting your money shooting in the dark.

[zpwn06]

Re: Real crappy mileage, NOOB question

putting a cat on the car and swapping in a high flow air filter isnt going to help his problem of 10mpg.

My guess is that your primary o2 sensors, you have 2 of them (1 in each header) are old. Mine went out and were causing the car to think it was running lean, thus adding more fuel. Replace your o2 sensors

agreed

[screamin 99]

Re: Real crappy mileage, NOOB question

get it scanned, dont throw parts at it i just learned that with my bonneville. threw 260 bones at the thing and didnt fix the misfire. took it to a shop and turned out to be a burnt plugwire

[ssms5411]

Re: Real crappy mileage, NOOB question

You can also buy the little scanners that will tell you what code is on and after it flashes 3 times it will clear your code. There about $40 and a great investment to keep in the car so if a light comes on you can just plug it in, on the spot and you will know the code right away. I also agree with the O2 sensors my driver side is not going above 900 at WOT or any other time, compared to the passenger side showing 933 and above. So my gas mileage has gone to sh!t this past month with average of 13 mpg. My wideband is working fine so I know my A/F is good. I'm going to change the O2 sensor here ASAP. Good luck with yours.

[gatormike69]

Re: Real crappy mileage, NOOB question

Great, thanks for all the great info. This is why I joined this board, I knew there were some good folks here who have all gone through these issues before. I'll take the camaro down and have it scanned at AutoZ and check in to getting one of those $40 scanners if y'all pass on the knowledge of where to purchase one? Thanks again........ together we'll get this ragtop runnin' right.

[zpwn06]

Re: Real crappy mileage, NOOB question

Great, thanks for all the great info. This is why I joined this board, I knew there were some good folks here who have all gone through these issues before. I'll take the camaro down and have it scanned at AutoZ and check in to getting one of those $40 scanners if y'all pass on the knowledge of where to purchase one? Thanks again........ together we'll get this ragtop runnin' right.

:wavey:

[gatormike69]

Re: Real crappy mileage, NOOB question

Thanks, just borrowed one from a buddy @ work and will scan the codes this evening and then clear them out and see what reappears. Thanks again. I will end up purchasing my own scanner soon. Was looking @ the book that came with the scanner and wondering what the MIL status ( with pending codes) and I/M monitors are. DTC I understand. Thanks