i had something like this in the 87-96 page but haven't gotten much of what i really need. i think i have a vacuum leak in my 89 351 efi. i got a gauge and at idle i had between 16-17 in, and i had it hooked up to a bonus spot on the firewall right beside the map sensor. what should the vacuum pressure be at idle cause i can't find it anywhere? then i checked the egr valve and with the engine not running it held vacuum, and when i started the engine and put vacuum on it the truck stalled, so i think that is working am i correct? then with the engine shut off i check various hoses and i put 15 in on them and they leaked down to nothing in about 30 seconds. the ones i checked were coming out of what i think were the carbon canister, that is the one down but the radiator on the passenger side correct? and i checked the one coming out of the egr valve and it wouldn't put any vacuum on it period. i figure that it wouldn't hold any because it is hooked to a solienod to make it have vacuum on it correct? the reason why i think i have a problem is cause i have been having a rough idle for awhile now, but it has started to get oil coming out of the breather tube. friday night after i got home from work i went to check the oil and i noticed the oil coming out of the tube and it was a light brownish color and kind of smelled like gas, there was also alot of smoke coming out of it. am i even looking in the right area? or is one where i just leave it alone til i can afford to buy a new truck, cause this is my daily driver and i right now i don't have a whole lot of money.
thanks for any help.

 

If you suspect a vaccum leak, just take a can of spray carb cleaner and spray all over with the engine running. When the carb cleaner gets sucked into the leak, you'll hear it. But your other symtoms could point to a busted piston or rings, and possibly a bad injector spraying too much fuel. You pulled the spark plugs to check em?

 

i have done the carb cleaner test a couple of times and found nothing. the thing that has me is it runs great at highway speeds but when sitting at a stop light it idles like crap. i have also noticed when in park it idles pretty good but when in drive it idles really bad.

 

if you think you have an internal leak try clamping them off one at a time. They make a tool.
or get it to AZ and have them pull codes.....go from there

 

Hello,
This is my first post and I am glad to have found the forum because I really need a second opinion on my '89 F-250 which sat-up for 4 years. I am pressing it into service again with some difficulty. It finally started even with bad gas in the tank and I've since, siphoned the bad gas out and replaced it with fresh. Problem: It still starts but won't idle properly...I have to use starting fluid. The local mechanics say I have to go through a costly gas tank R&R (theres TWO on my Ford). + clean the lines..etc. because of jellified gas down in the bottom. I hope there's another solution. The mere fact that it will run and sounds powerful as ever, tells me that the gas lines can't be a major problem...Any advice would be greatly appreciated.