This is for a 93 F150 XLT 302. Idle is just a tad rough and there's a slight surging going on above about 30 MPH. Just put in a new TPS 'cus it was easy but that didn't help. Haven't checked the fuel pressure. I've had a few guys tell me to check the MAF but there's not one on this model as far as I know. Also have new plugs, wires, dist cap, etc. Any ideas?

 

fuel filter?

 

Vac lines?

I think what you have is a MAP (Manifold Absolute Pressure) not a MAF (Mass Air Flow).

 

Yep, no MAF, only a MAP. Haven't replaced the fuel filter yet 'cus the previous owner said he replaced it prior to getting it smogged back in November. I've replaced a couple of vac lines but I think it would be good to replace them all. Sounds like it would be a good idea to go ahead and replace the fuel filter as well since it's pretty accessible.

 

yeah its easy to get to and its only what like 7 bucks or so i cant remember but you cant trust other people ive always changed all fluids and filters in a used vehicle just becus its easy for the seller to say he did it but you never know for sure

 

Just got a filter for, yep, $7! I'll get it installed as soon I get a chance to break away from work. Thanks for the input guys!

 

LOL, also check your air filter, had a clogged one and was giving me a heck of a time. Good Luck with the fuel filter

 

Before attacking the fuel filter, read this caption carefully:



...and make SURE you have the correct (long-nipple) filter before snapping the fuel lines onto it. Also read this:

 

Got the right filter and now I see why I'm having a hard time pulling the feed line to the filter off the old filter. The output line from the filter came off without the tool. Should I replace the line? Thanks again for all the great info!

 

Why would you replace the line? If the bail inside is damaged/missing, just buy a new fitting & swap the bail into your line.

 

OK, replaced the fuel filter, coil, plugs, wires, dist cap and rotor, and properly routed and separated the wires and no change. Checked the fuel pressure, 35lbs at idle with the pressure regulator vacuum hose attached, 45 without the hose attached. Tried spraying carb cleaner around all the vac lines and didn't see any indication of a leak. Also need to add, there's a bit of hesitation on initial accelleration and if I'm going at a steady speed, usually slow but it's there at higher speeds to a lesser degree, there's a definitive bog when it up shifts and a press on the gas a bit at the same time. Any ideas?

 

If you've got the plastic lines that Ford puts on, it's sometimes near impossible to see a vacuum leak. With it idling, spray carb cleaner on the vacuum lines, around the upper plenum gasket, and the throttle body gasket. If the idle changes, then spray that spot one more time to make sure it changes again. If it the idle changes both times, you found your vacuum leak.

 

Just tried the carb cleaner trick again and zero luck. I sprayed everything I could find, several times, and saw no change in idle speed.

 

hmmm with everything youve replaced it should be runnin great maybe its somethin in the computer system sendin whacky signals i dunno steve83 is pretty good he might have somethin

 

I was having a real problem with surging and bucking, but it would backfire too. Thsi was after my truck sat for quite awhile. It ended up being my distributor bearings, I pulled the distributor and spun the rotor by hand, and I could feel the drag. It even squesked really bad. You might wanna pull it and try it, I dunno. make sure you mark the block\distributor and the rotor\distributor so you get the timing somewhat close when you put it back. I'd still set the timing(with a light) again just to make sure its right.