Was getting 17 to 19 mpg. Suddenly dropped to 13 mpg but run well. New plugs, wires, coil pack because developed miss-fire on 2 & 5 but this was after the problem started. I have been putting Sea foam & lucas injector cleaner in for 3 tanks. Seams to do slightly better but at idle on these cold mornings fuel consumtion is terrible. While I am waiting for my heavy equipment to warm up fuel average will drop in 30 mins from average 18 mpg to 12 mpg or lower? Any suggestions? I am very much mechanicly inclined, 2 race car's, 160 personal autos, rebuilt many engines etc. Got me and my buddy, 1st class mech w/ 31 years exp stumped.
also, have problem w/ atc varying constantly, w/ max air only in summer. The black box behind the console control, does that control atc temp adjust. Thanks Mac

 

Your engine temp sensor usually faults the other way, but it could be acting up. They run about $25.00 and fairly easy to replace.

The other possibility would be the EGR valve sticking or running open when it shouldn't.

Hope this helps,

Bob

 

Thanks Bob, Would I not have a check engine light if insufficient air flow or to much air flow. Had a problem with a Ranger I had a few years back. Check engine light, insufficient air flow to EGR. Was not the EGR, nor the silonoid but rather the sensor located on the front of engine manifold that controls all egr component functions. It could very well be the egr and I will check it but I am baffaled at no ck. eng. light an seems to be running well. After I check it I will let you know. Mac

 

Might have it scanned for codes even though you're not getting a light, under the category of "couldn't hurt".

 

Tow_Guy has the right recommendation - have it scanned. He usually points out Autozone will do it free for years after '95.

Normally you get codes for malfunctions, but some of them you have to find yourself. By design the system either works or it tells you what's wrong. I wish it was that simple.

I'm more old school with a vacuum gauge, pull the plugs or plug wires one at a time, etc., etc., etc.

Let us know how you come out. There's a lot of good tech people on this forum that can give you some help. If one guy doesn't know it, the other does.

Later,

Bob