I’m getting 10mpg highway in my 3.0 (stick) Air intake and filter are clean. Plugs look fine. No codes- but the rear antilock light comes on intermittently. Driving gently in warm/ hot weather with 10W30. No smell of gas. Ran Gumout injector cleaner through it. Have no EGR system… trying to formulate a list of next things to check. Any suggestions are kindly appreciated.

Ryan

 

brakes dragging? head gasket ok?

 

I’m definitely going to check the brakes next- the head gaskets are brand new. Thanks for your thoughts. I’ll post findings

 

Engine management going into closed loop??

My '95 Runner gets 17.5 to 20 MPG, depending on conditions.

 

Put timing light on it and verify timing this can also show possible issues with your ignition system. Should be easy enough to jack up the rear and spin the rear wheels to check for brake dragging, if they are dragging pop the drums off and check for broken springs or hardware. If it all looks good tighten your adjusters and see if that helps. Iirc the rear abs is also integrated into the power steering in these trucks? Even missing 2 cylinders I was getting above 10 mpg so something is definitely amiss here. These trucks are fairly simple efi so either the truck is having to work too hard or you’re running rich. If your plugs look fine and you get the abs light brakes are definitely the next stop.

 

I was able to check today and no brake dragging at all. I’m going to check timing next. Thanks again for the thoughts, fellas. Will post findings.

 

You said headgaskets are new. Did the poor mileage develop after the gaskets were replaced?
If the vehicle was running rich it should be throwing codes left and right. whenever a customer complained of poor mpg there were only a few things to check. timing, plugs, etc. the recent gasket replacement may offer a twist, though. For the sake of asking, what plugs are in it now?

The anti lock light coming on typically means the system is disabled, not that its engaged.

 

I never drove it before the head gaskets were replaced. The plugs are NGK. I haven’t checked the timing yet since I don’t have a light handy. Thanks for the input. Here are a couple of the plugs for reference.

🙏

 

Update. Swapped out plugs and then tore the foil contacts out of the AFM being a jackass. Now it's throwing all sorts of codes and wont run. OEM replacement \ should arrive Thursday. I guess I can check Air Flow Meter off the list.

 

Those plugs look awfully old. Someone did headgaskets and put those back in? Might be worth scrutinizing the work.
check timing, maybe do a compression test, fill up with top tier gas and do another mileage check.

 

Okay, so I got the new AFM put on- she started right up. The timing is fine, new plugs, new air filter, no brake drag... I've not yet done a compression test and I'm not sure how to check "Engine management going into closed loop??" but I'd guess that this would cause a check engine light at the EFI?

Maybe these plugs will improve the mileage- I'll see if there's any change this weekend. Thanks again for all the suggestions. Ryan

 

Failure to go into closed loop will not light the check engine light.