I have a 92 5.0/auto with a rough idle and it shakes when lugging. The fuel filter was really dirty. Ran a can of Seafoam fuel system cleaner, no improvement. Ran the codes (not running) and nothing to indicate a problem, just a couple of weird things like low a/c voltage. Should I do a running test?

Assuming the injectors are dirty, are they ever so bad that they should be manually cleaned (i.e. removed)? It also doesn't start realy easy when warm, have to crank for about 3-4 seconds.

Thanks,
Biederboat

 

after doing the seafoam did you replace the plugs? might need a tune up new wires,cap/rotor and timing set to 10*btdc with spout connector removed. how many miles on the motor? is it burning any oil?

 

I didn't replace the plugs or do any tune-up work. The motor has 92K. Should wire, rotor, cap be replaced before 92K? Engine doesn't burn any oil.

Thanks,
Biederboat

 

lol....are you still running on stock wires, cap, rotor and plugs??


sounds like you need to do a tune-up and if its still rough, possibly check for vacuum leaks

 

I replace my wires, cap, and plugs about every 20,000 miles or so. Just good common sense. I use to buy the platnium plugs but the last two sets had the ceramic seperate from the plug. I've switched back to the good old motorcraft plugs, never failed me yet.

 

You might try checking your fuel pressure. A bed pressure regulator can often cause this condition. Good luck.

 

The early 90s injectors were prone to clog. The later ones have a different pintle design that works much better. I would try the tune up, test fuel pressure, also try driving the truck with your scanner hooked up. If it runs good then, you have a voltage drop to the fuel pump. When the test connector is hooked up the fuel test lead is jumpered directly. After that you are looking at the injectors. Pull them and ground one lead, then apply 12v to the other. You should hear a good audible "click" if so that one should be good. replace the others if they do not "click"

 

yes replace plugs,wires,cap/rotor and set timing to 10*btdc with spout connector removed. this will help alot

 

I checked cap and rotor...wow! It looked good on the outside and pretty bad on the inside (severe pitting). I'm going to replace cap, rotor, wires and plugs just for good measure.

Spout connector, is this the little black rubber cap up on top?

Also, as of recently and in addition to the above, I've replace the fuel and air filter. Is there anything else that needs regular replacement on these (that could affect driveability)? I don't have a manual yet, hope to get one soon.

Thanks,
Biederboat

 

I had the same problem, but when I changed back from platinum plugs to regular motorcraft and but the heavy duty plug wires on it ran fine. By the way what is the acceptable fuel pressure range to run on the 5.8L?
Some auto parts can clean the injectors for 1/4 the price of new.

Thanks
Herc 5HP

 

you may want to replace the pcv valve and coil. Get some autolite standard plugs and maybe an msd cap and rotor. and for a coil, I would suggest the msd blaster tfi coil.

 

If I remember right 40-50psi should be good. You can get an injector cleaner that is one or two cans of cleaner and screws into the fuel pressure test fitting. Hook it up and run the motor per the cleaner's instructions. This may help. It is not cheap, but not outrageous. The SPOUT connector plugs into the dist. someone else may be able to give the exact plug. I am knee deep in body work right now.

 

I run fuel injector cleaner in my tank every 3-4 fillups. And I am sure to buy enough for the 32 gallon tank. Simply pouring one bottle of cheap cleaner in the tank once a year is not going to cut it. Bad gas it not usually a problem these days, as most gasoline in the United States is detergent and designed for fuel injection. You do not have to buy the fancy gas where they say that you can "drive your engine clean." Back in the days when fuel injection was just emerging, and gasolines were not all detergent and not formulated for fuel injection, it was essential to know what type of gas you were purchasing and to change the fuel filter more frequently than is required. Not really so today, at least in the Continental US.

These days, as long as you change the fuel filter at required intervals, and run some cleaner in it at a regular schedule, then you should be fine. Even the injector cleaner might be overkill; but like I said I put 2-3 bottles in every 3 or 4 fillups. For that type of maintenance cleaning I simply use the Snap! brand or whatever else they have at the dollar store. They all use about the same stuff anyway, and who wants to add $10 to an already expensive fillup? So I use whatever is cheapest as maintenance, and once in a while, maybe three times a year or so, I will spring for the expensive stuff. If you read the packages, they have different ingredients at that price range and have more benefits. But it adds $15-20 to the cost of a fillup. So 2-3 times a year for the "good stuff" is plenty. And again, you have to buy enough for your tank, which usually means two of the expensive bottles. If you want to save some dough, just fill up to half a tank when you want to do a cleaning with the expensive stuff, and then you will only need one bottle of the good stuff instead of two. Just be sure to run that half a tank almost to empty and not put more gas in in between, to get the benefits of the expensive cleaner. Also, if you check the sales, often you can get the "good stuff" on a 2 for 1 special, which is perfect for us Bronco owners with large tanks. Then you can get enough for well under ten bucks. I try to buy a few of them when I catch a 2 for 1 sale.

I have literally had fuel injector cleaners work miracles. Even the cheap stuff. My Bronco has always been clean, but I can recall once when I was broke and needed a car badly, so I bought a 1984 Chevy Cavalier wagon (I lived in Florida and the car had cols A/c!). Anway it shortly started to idle really rough, and would die when the A/C was turned on. I was thinking that the motor was toast. So I put in ONE bottle of the STP "super concentrated" fuel injector cleaner, it comes in a black bottle and runs about $3; I put that in in the afternoon and drove around some to do errands etc. and by the next day the car idled like new and did not stall when the A/C was on. I actually liked that little Cavalier in its own way - it drove smoothly, had cold A/C, it was clean and as a station wagon it held all my fishing gear. And it never left me stuck anywhere. I finally sold it because it developed a knock. I had bought it for $780 and sold it with the knock for $400. I knew the gal who bought it, she had it fixed and it turned out to be a cracked flywheel. But I used that $400 plus some more that I saved up to buy the sweet 72 F100 that you can see in my gallery.

ANYWAY - if you think that my fuel injector cleaner schedule is overkill, or a waste of money, consider this; my Bronco with 130K on its 5.8 does not have any stumbling or flat spots, not even right off idle. And speaking of idle, the idle in my Bronco is so smooth that the motor can not be felt, it has absolutely zero feeling in the wheel or anywhere alse and sometimes I even think that it is turned off, if the radio is up. I attribute these things to my use of injector cleaner on a schedule.

PS - If you feel that the injectors are causing your problems, you can go to Jiffy Lube or somewhere like that to have them blown out and cleaned for under $100. They do not need to physically remove the injectors to do this. If you are going to go to the trouble of removing your injectors to clean them, you may as well just buy a new set and swap them out.

 

Thanks again everyone, I got to thinking also why the cruise control wasn't working. Hmmm...vacuum leak??? Sure enough, that solved two problems. Well, almost, it still idles a bit rough but I'm suspecting the new rotor/cap as bad as it is will take care of that.

Biederboat

 

when you go to buy your parts pick up a manual at that time. its a must have item for sure