Hey everyone. Have been a lurker for a while but I am newly registered to yota tech and wanted to see if you all could help me out. I have a 94 pickup with the 22re and 31X10.50s on it. Right at 190,000 miles on it. Everything else is stock outside of a K&N air filter and the cat wasnt there when I bought the truck.

In the last week my gas mileage has dropped from around 18 to 13 and it has started missing when I hit any bumps. It hasnt seemed to have had any drop off in power though. The plugs, wires, and fuel filter were all replaced recently and it has ran fine up until the last week or so. Everything is tight that I can find. It does sound like there could be a small exhaust leak up towards the headers at times. I cant find it though if there is.

Just wonderin if any of you have any ideas on what I could check before taking it to a mechanic. Thanks for any help you can give me.

 

Possibly a bad EGR valve? or O2 sensor?

The gaskets near the O2 sensor (where the header connects to the exhaust can get pretty crusty...

I think you should have a maintence light if either of the conditions i mentioned above were met...

Hopefully someone with better diagnosing skills will chime in.

 

I check engine light has been on for a little over a year. When I had a mechanic hook it up to diagnostics it came back as the O2 sensors. He told me that it wouldnt effect anything and wasnt worth the money to fix. How bad of information was I given??

 

O2 sencors will do more than you think; they can make the motor run rich, which will in turn burn more gas, probably make the truck stumble a little because of the incorrect fuel mixture, and will definately make you mpg go down the drain... sounds like the mech just didn't want to climb under your truck, even though it's an easy replacement. on my 91 federal emmision PU, there's only 1 O2 sencor, and it's all of 2 bolts and a plugin.

Before I did any work though, I would check the codes yourself and see what they currently say, then erase the code and see if it comes back, and if it's a pretty important problem, then it wont take too long to come back on, then read it again and compare. Search the YT site, there's plenty of write-ups, how-to's, and threads devoted to code retreival/clearing.


Now with my O2 sencor it did not throw a code, but after testing it with a mulitmeter, it was way out of spec...

 

other then grounds...like other have said O2 sensor and check your TPS sensor while your out there...

Make sure you write your tps reports with the new YT format