new to here but have worked on fords all my life ,after 40 years (not proffesionaly but its a practice)and now to the point stumped am i 91 ford van 5.8 ran fine only 65000 miles new tune up pl,cp,wire,filters a little trip and now it runs like crap I love my van ! help please. runs ok at 55 but trouble getting there misses no backfire great milage but no power .I tried injector cleaner dry gas new oil nada nothing stays the same .

 

OK, Hanky, check me out here.
The firing order of this engine (and certain 5.0L, with cams, like the Mustang) is: 1-3-7-2-6-5-4-8. I'll bet Hanky his next drink the problem is with the wiring to the plugs. Since the dist. turns counterclockwise, once #1 is established, the rest is a straightforward application. Please pay extra attention to the routing of wires 2 and 7, as they go between 1 and 3 and 6 a nd 5, respectively, between them to cancel out any induced backfire.
Otherwise, check the basics. Fuel pressure, EEC codes, base compression, etc.

 

Question is, did the trouble develop AFTER the tune-up work, or was the work performed to remedy the trouble? imp

 

Hi guys!
I almost was going to ask how he changed the wires, but you beat me to it.
Also, imp asked my next question.
Many times, as I'm sure you guys know, more problems are solved by just asking the right questions.
From what was posted the plugs, cap and wires were the only things changed that might affect the performance. I guess we'll just have to wait it out and see what the replies are .

 

my thanks to you all but,the problem got worse over a period of time ,changed the wires seemed better but the wife went on a trip and when she got back it would not run rioght ,checked the wires right on the money,tps was bad changed ,plugs too,egr ,timming chain had 3/4 play now that is changed and yes ftriple checked for correct marks,fuel at 40 no drop,does not lope now but wont run if it were an older motor i would say points open too far,misses and backfires with no change when plug wires pulled to find whitch one it is ,it wont run right no power no tapping valves too.

 

I don't see any mention of changing the fuel filter. Unless that and the air filter were included in the "filters"
If it idles lousy I would check the EGR valve and system for too much EGR and /or a possible vacuum leak. Those engines were loaded with vacuum lines and any one or more of them could be cracked or off.
Something else to consider, a possible plugged converter which is more likely than a trans converter stator not locking up. Those are possibilities ,but I don't remember seeing the answer as to if you had the problem before you changed the parts.
If you have a vacuum gauge , connect it to a manifold vacuum fitting and rev up the engine. If the vacuum continues to drop and go lower and lower there is an exhaust restriction. If it is the catalytic converter , they are big,and expensive. Let's hope it's not that.

 

One more thought to Hanky's checks. Unplug the SPOUT connector (which kicks the computed timing out of the system) and see if it gets better.
You could also do a vacuum drop test to see if the cats are plugged; it might be easier. Just food for thought.

 

i had the cat checked and no problems where seen also fuel filter is new and also fuel pressure is at 40 with little drop /37 psi when throttle depressed

 

Did this problem exist before you changed the cap and wires? Need to know this because we can run all over the map looking for a problem. If it came up after the repairs then we can confine our efforts to the ign system.

 

The problem was a slight miss and what I thought was a exhaust leak [small] and now is all over with no particular cylander the culprit ,now have checked no hung up valves or bent rods seems all the fixes needed to be done and now the true problem might be revieled ecm and pickup in the distributer .