ground issue?

[RBrandon]

help. '93 5.0 has following isues: in AM, doesn't want to idle at first, then will almost purr for next 45 minutes to work. in PM, cranks with loping idle and VERY strong gas smell. runs like hell with no power and missfires occassionally on way home. Can pull off, shut down for a minute, restart, and runs a little better. Have had three check engine lights come on on way home but they will go out after 10-20 minutes and she will run halfway decent again. checked timing: spot on. checked fuel pressure, fine. All I can figure is to check for a good ground on the computer and here's why: I dont think my o2 sensors AND TPS and MAP are all going out at once and my symptoms seem to cover more than just one. Further, if the PC latches a code I wouldn't think it would vanish mid flight. Normally have to use a scanner or unplug the battery to reset a latched code so I am thinking loose connection to the computer somewhere. If anyone knows otherwise or can point me in another direction please let me know. It's getting a little worse with each trip to work.

[old_master]

Could possibly be an intermittent ECM ground or battery power issue. Or possibly the power up relay for the ECM is not holding. What DTC's did you retrieve?

You'll need a scan tool that can access the history file, the DTC's are stored there. Disconnecting the battery will not clear them. The only way they are deleted is when the problem does not occur for a given number of consecutive drive cycles, usually 20 cycles, depending on how the ECM is programmed. Or with a capable scan tool.

[rhandwor]

Check for a loose computer ground next to the Pcm in right hand kick panel.
Check grounds at the battery and small ground wire next to the large ground.

[RBrandon]

I haven't pulled the codes yet. I will run down the grounds tomorrow. For grinns I changed out the fuel pressure regulator and cleaned the throttle body, etc today just because it has never been done and I needed the downtime since Ford designed the regulator such that the screws are bottom up. (jerks) Any way, it cranked up way better than it had in the heat of the day but I missed a piece of gasket and was peeing water so I shut 'er down, cleaned up my mess, rechecked my surfaces, and put enough permatex on there that I will be cussing myself next time. I'm off tomorrow though and except for some steaks on the grill, I will spend my free time checking grounds, etc.

[RBrandon]

replaced the fuel pressure regulator, cleaned the throttle body, cleaned the maf sensor, solved the one problem but now it is idling around 1.2k like I am hitting the gas. dont even have to touch the pedal in first gear... double checked the timing for grins and it's at 10 btdc with the jumper out... someone help me before I torch this beoch. I dont know much of anything about fuel delivery aside from pumps, filters, and now pressure regulators. Dont know if I need to adjust a cable after having the throttle body off or if I blew gunk into a sensor or what. now I'm beyond annoyed and I feel like a frickn moron at intersections idling wide open. ooooh. look at my loud car that needs a paint job and new headliner. fyi. it takes a few seconds for it to idle down to that point as well. when I am coasting to a stop it idles at around 1700 and by the time I settle back down on the wheels it slows to 1200.

[rhandwor]

Look at the work you did on the car. If you unbolted throttle linkage you may have moved how it was set. Did you reconnect the vacuum line to the fuel pressure regulator. Are all plugs installed correctly.

[lilred86]

There's an idle screw under the throttle body next to the linkage. Back it out some while it's runnig.That should help the idle.