i have a 1994 f150 4x4 with a 5.0 and it runs but not good. when you drive it it runs like its lean and it pings when you step on the gas i have replaced the ecm, dist. ing mod, egr valve, plugs, cap rotor, mass air flow sensor, coil, tps, fuel pressure regulator, checked the cat with a pressure gauge, checked fuel pressure, any other ideas?

 

Wow, that's a pretty good list there. I would be pissed at that point. I'm just going to ask you a few more questions to get more info on the truck for all eyes to see. How many miles on it? Are you throwing any codes? How's the o2 sensor? I would be seriously considering the possibility of an intake leak. Go get yourself 15-20 feet of vacuum line and replace all of them. This one is just some time and maybe $15. If that changes nothing, I would start in on the gaskets. There are more efficient ways than guessing though, as you have found out. Good luck to you.

 

180,000 and i forgot the new o2 sensor and no codes and i already went through the vacuum line and i have good vacuum with a gauge. i have auto-lite platinum plugs in it and someone told me to change them back to motor craft stock plugs

 

Yes on replacing the plugs with just Autolite or Motorcraft Copper plugs.

When you say no codes, did you get a system pass of 11 or 111?

What is your running fuel psi and WOT fuel psi?

 

I'm sure it was 111 and i don't remember the fuel psi because it was a long time ago this problem has been going on for a long time and I left the truck set for 6 months because of it.

 

Ok...

Then we are looking at a lean issue if you say it pings when you mash on the gas OR lots of carbon buildup on the pistons and/or heads.

Need to post your fuel psi readings.

Have you tried 89, 90, 91, 93 octane fuel? What haven't you tried?

Remember, aftermarket can equal JUNK. What's Motorcraft and what isn't?

What is your timing set at, with the SPOUT jumper removed?

 

I've tried better fuel and checked fuel psi on both tanks but it was over 6 months ago so i don't remember what it was. timing is at 12 with the spout out

 

somehow the carbon sounds like it could be an idea, there was a lot in the trottle body when i cleaned it

 

I'm starting down the same path - replaced EGR, plugs, dist cap and rotor, throttle sensor - fuel tank had a leak as well so replaced that and sending unit.

My continuing issue persists though - engine loses responsiveness and bogs down intermittently - it does seem to appear consistently after driving for about 40 miles, could be temp related - it can come up soon after getting on the road, but becomes worse after warming up. It seems to almost go into limp mode, not responding to throttle and gradually loosing power.

No backfiring or missing though. after dropping down to about 60 (whether I like it or not) I can floor it and it will respond again for a while, but it will eventually bog down again. If I stop the car and turn it off for a while it seems to get better - for a while...


Also pings when I give it gas, maybe that's a different issue or another symptom.