1993 F-150 Almost Dead!

I've got a 1993 F-150, 5.0 everything stock with no mods and just shy of 85000 miles. I have not ever had any problems with my truck until recently.

Now
(All at low rpms)
1. Missing while accelerating (when I am able to accelerate!)
2. Really bad hesitation especially under a load.
3. No power.
4. I have to baby the gas to get the rpms up, but it still misses even at road speeds.
5. No problems with gear changes until OD. Shifts into OD drop the rpms and the hesitation comes back.
6. If I turn off the OD and make rpms stay up it is almost driveable, but its getting worse.
7. KOEO codes - OK
8. Memory codes 211, 334, and 543
9. Engine runing codes - OK

The truck has new plugs, wires, dist. cap and rotor, tune-up, EGR sensor, air filter, new fluids.
At idle the truck will not go to WOT quickly. If I really get on it, it doesn't even respond. I have to baby the gas to get the rpms to climb.

Any ideas would be appreciated!

 

Sounds very similar to my truck. I have a 91 F150 with the 4.9L. I can't remember all the codes, but I'm thinking Idle Air Controller or plugged catalytic converter.

 

Check for back presure problem. You don't have a lot of miles but the symptoms do sound like maybe a plugged exhaust. If you have a vac. gauge check that you have proper movement when you open the throttle.

 

I'll bank on a new cat converter myself with this one.

 

dbev, if you don't have a vac guage then another simple little trick is to get another person to slowly increase the rpm while sitting in park. Put your hand(s) over by the end of the exhaust and feel the pressure while idling and while the rpms are being increased. If the truck start to act up and the pressure at the end of the exhaust goes down, you have to replace the cat or just get rid of it depending upon the emission laws in your state. I had this happen with my '87 and I couldn't get it to go over 2000 rpm in any gear. The mechanic did this simple test and we changed the cat and all was well again. Good luck and let us know what it is.

Have Fun & Keep on Truckin'
Dean

 

Wow, thanks guys for the suggestions. I didn't expect to get so much from my first post. This is a great forum, thanks again.

I did the exaust check of the cat this evening but it doesn't seem bad. The overall exaust system is in fair to poor shape and I have a friend who has a two-one replacement cat that I can get pretty reasonable. I am going to put it on and I will let you know if it helps.

Thanks again for your replys to my first post. I guess me and my truck will hang around here and take advantage or your help more often, that is if I can get it our of intensive care!

 

dbev...Another thing you might look at if all the above suggestions don't work is the timing chain. As a 302 approachs 100,000 miles, the timing chain can get pretty sloppy. I had this happen to an '87 F250 that I had.
Good luck,

MR

 

i once forgot to plug in the mass air meter on my stang and it acted the same way. check to make sure its plugged in. any work done to the truck proir to the problem starting

 

Vacuum leaks can cause all sorts of mayhem. And, unfortunately, those vacuum hoses are not always the best. Check them out, especially those on the cruise control system.

 

Thanks Guitar_Stitch, Pestco1, JOHNnDENVER, IzzyEddy, MROLDV8, lees99f150, and cheri/ck for all the help and suggestions. I worked pretty hard on the old '93 this weekend, but no luck.

I finished changing our the cat and actually ended up replacing the whole exaust system since it was beginning to look pretty rough. I put on a 2 to 1 replacement that fit like a glove. If anybody needs to replace yours, this one is pretty cheap (as converters go) and was a snap to get on. However, it didn't seem to improve the performance any. It will make a difference when I get whatever is wrong fixed; so thanks to all of you who suggested it. The truck will be better with the new system.

I didn't get to check the vacuum system out this weekend, so I guess I will start with it next. I did check the idle air controller using the steps in my Haynes and it checked out ok. I am going to be traveling for the next week or so, but when I get back, I will let you know if I find anything in the vac system.

Thanks again for all the help!







I had the timing checked and found it to be ok.

 

Check your fuel pressure. Your pump may be crapping out. When you go wide open throttle the pump may not be able to keep the pressure up.

Also clean your mass air meter.