Hey guys,
There seems to be a problem with my truck. When running down the highway, it sometimes spits and sputters. And when idling, it misses every now and then, sometimes driving slow or idling, it will just die, even sometimes when I just let off the gas. Since I just got it, I put some injector cleaner and a 92 octane fill up. Plugs are new. My first thought was the fuel filter. It looks recently replaced with a wix. however after an hour and a half and not getting the in flowing side off, I hoped that it was something else. I had attempted to pull engine codes, and got 133 or 331, either way thats not a code, so I have to try that again. I'm thinking that maybe the cat is stopped up. Has anyone had this problem before, or should I wait for engine codes? Light comes on, but will not stay on. Previous owner said something about EGR, but he was not very mechanically inclined. One of those that check the tire pressure if the truck wont start.

 

check your timing, it should be at 10*btdc with the spout connector removed. also check out fordfuelinjection.com for all efi related info. Pull some spark plugs and see how they look. also see what brand/type they are. these vehicles only like normal copper plugs. also pop the dizzy cap and see if it along with rotor needs replaced. some people feel a tune up is just replacing plugs and calling it good. the cap/rotor and plugs wires all need inspected and replaced if old/worn or originals. I would also check Fuel pressure at the rail with a gauge.

 

Kem, I've seen the advice to check the fuel pressure at the rail before. But I havent seen what the reading should be. As far his problem, I dont think the converter is plugged. When that happend to mine, It would idle fine and run rough at speed. I would suspect spark plug wires.

 

my bad i should have posted that. proper pressure should be 39-45psi at the rail with key on engine off or engine running.

 

Spark plugs are on the list for repair, as is cap and rotor and other main tune up items. A work in progress. I didn't think it'd be any of those, since it was fine then just started acting up. But I could be mistaken. Will see about checking fuel pressure as soon as possible. I know with a problem like that it can be any number of things.

 

Ok, update time. I replaced the Spark plug wires with some new accels, The cap and rotor with MSD replacements, and even the bottom distributor cover(had heard that a crack in this could cause problems). It still runs bad, if not worse. It seems to be getting progressively worse. It seemed to be running slightly rich, but not so much anymore. It will start then run and peter out. Right before it starts sputtering and dying, the voltage drops down. Engine codes I got were 122 and 334. Throttle positioning sensor and EVP. Had thought it may have been tps. I do not know what EVP is. Could these be whats causing my problem?

 

neither of those would cause this problem. both are related to the smog equipment. I would suggest checking your fuel pressure and double check your timing. what did you gap your spark plugs to? and double check your plug wiring firing order as well.

also go into the control panel and give your vehicle specs in the signature area so we know what year vehicle and what mods it may or maynot have.

 

The TPS is a problem if it is below the minimum voltage. The minimum should be close to 1 volt and max of 5 volts for WOT. Spitting and sputtering in and old carbed engine as you opened the throttle was a bad accelartion pump in the carb, in this case the accelaration pump was replaced by the TPS. The EGR can also cause some miss if it is held open the entire time the truck is running as it can not get enough air in to compensate for the "poisoned" mix and then the injectors have to be leaned out to reduce the air fuel mix to the right ratio. You still need to check the fuel pressure at the rail as it can cause a rich burning system with too much pressure.

 

Ok, Thanks for the help? I know the firing order is correct. I am pretty sure the timing is also correct, when the truck is not sputtering it is running good. I am ashamed to say it, but I did not Gap the spark plugs. I've been buying them for my car and they are always gapped right. I just grew tired of checking and plain forgot to check these. I have a good multimeter, How would I check the voltage on my TPS? Also, is there a way to check the EGR? Do I need it? All I can see that its doing is causing a bottleneck in power. Thanks for all the help; past, present, and future.

 

Fordfuelinjection.com has alot of helpful info on how to probe the wires of the TPS. Look it over real well and probe to find out if the TPS moves steadily up the voltage range or if flat spots are present. If there are flat spots then the computer doesnt know the TPS is opening. The EGR can be tested with a hand vacuum pump, similar to the vacuum brake bleeding pump, with the multimeter. Good luck

 

Seen bad ect(engine coolant sensor) cause over rich prob.(idle rough, stalls ,surges)Use metal at threads type---don't use one with plastic threads.EVP code, evp is bolted on top of egr valve(egr position sensor)Loosen three screws on evp and re run codes should go away, replace evp.NOW if the Egr is not seated close at idle rough idle will occur and evp is just reading what it sees(wants to see closed at idle) open egr causes rough idle and surges and LEAN situation-- injectors will go rich when oxy sensor sees this LOL Blue

 

Wow, so much electrical CRAP. The TPS is definetly shot, the whole truck runs better without it even plugged in. I bought a new one, but looks like I'll have to take the throttle body off to get to it, since it is underneath. As far as the EGR, is it possible to remove and clean the valve? I'll check connections on the EVP, before I go and buy one. While I'm at it, I'll prolly buy a oil sending unit and engine coolant temperature, maybe an O2 sensor while I'm at it. Hopefully it will run good enough for me to tinker with around the house until I can buy a new radiator, since mine busted, and then I'll start on the broken leaking exhaust. Yay! Right after I dump what seem like about a grand in it, the engine will prolly give out. That'd be my luck.

 

only replace what needs replaced. the codes are there to show this. the tps is the right start and yes you can clean the egr.

 

I wouldnt remove the egr from the exhause because I have found that the threads strip real easily went doing so. You should, however be able to unbolt it from the upper intake and lean it away from the engine while it is attached to the exhaust tube and clean it that way.

Like kemicalburn's said, only replace sensors that show a need for replacement, i.e. out of voltage range tolerances or resistance tolerances. It can get expensive swapping parts when there isnt a need for replacement.

 

A little heat on the large nut usually helps when removing exhaust tube from EGR valve. Seen very few stripped threads on EGR valve--- have broken off threaded part on EGR valve though. I would not pry or bend that exhaust tube BECAUSE they break with age very easy at flex section under heat rapping. 5.0 requires removal of upper intake and new part is now solid, no flex section and they don't line up real easy. 5.8 goes straight down to front of RH exhaust manifold. Fitting in manifold must be removed from manifold and replaced with new style that comes with new ford tube. Like K-BURNS only replace-repair what you need. Tune ups, filters, etc., (unless just done) are never a waste of money- unless you use wrong plugs. Cleaning throttle body is cheap DIYS and cures many probs.Stick to what codes you got.Clean,repair,replace what is ness. and I think you will come out OK. 32 years as a Ford Tech at same dealership has taught me a few things but you still learn something new every day. Regards -Trublufords in Appomattox Va.