92 2.3 liter, I replaced all plugs and wires, fuel filter. There is no CEL on.

WHen you crank it over it starts up but has acts like it has a hard time running at idle. If you give a little gas it clears up. Even after its been running a while if you start coasting in neutral (5 speed) it doesn't idle well.

What should i check next to clear this up?

 

Check the timing.

 

Can you get your hands on an OBDI scanner, Just because there is no CEL. it doesn't mean there is not a pending DTC on the computer.
Check codes

EGR system
or even the EEC may need looking at.

 

Well it could be a number of things, but seeing as how it only misbehaves at closed throttle, maybe pull & clean the IAC, as it's often the culprit of idle problems.

If cleaning it solves the problem, it may not last for long, but at least you'll know what to replace if the problem returns

With the vintage of this ride, I'd also have a close look at ALL vacuum lines & their connections & this would include the PCV valve & it's hoses & the vapor recovery system.

I like khadma's idea to have the computer scanned for pending codes.

Let us know what you find.

 

I forgot to mention i also replaced the PCV valve. All the vacuum lines look good, ive replaced some that were not.

I did clean IAC couldnt tell a big difference. Auto zone wanted 80 bucks for a new one so was trying to get a solid diagnoses b4 paying for a new IAC.

What is the rubber hose on top that connects to the TB / valve cover?

Will pull codes tomorrow and post back.

 

Still havnt pulled codes yet, another thing to add is it only idles ruff with ac on.

IM still curious as to what is the rubber hose 90 degree bend that goes from the throttle body and valve cover. Im noticing a little oil is escaping the end that goes to the valve cover. Should i just put a clamp on it or is there other problems?

 

I'm not a 4banger guy, but it sounds like the rubber hose your talking about, is part of the PCV system plumbing.

If it is & it's weeping oil, maybe you have excessive cankcase back pressure.

Are you certain you didn't install the new PCV valve backwards & that it's the specified Motorcraft one for this engine & not some third world after market one????

Maybe you have excessive piston blow-by.
How is the engines compression numbers????

On the rough idle, are you certain the IAC is going to "throttle-up", when you turn the AC on?????

If you don't want to spring for a new IAC, check out the salvage yards for a low milage donor!!!!

Just a bunch more thoughts for pondering.

 

PCV is installed correctly, not sure on crankcase back pressure or cylinder compression. I suspect the IAC, i pulled it and cleaned it and it was pretty black inside. Bought this truck for a gas saver and its okay about 20 mpg but i keep spending instead of saving
I might spring for a new IAC and see if that works. The truck does idle up after ac comes on but its like it takes to long or doesnt idle up all the time. If you just give it a very very little throttle it clears up and acts fine.

Thx for input pawpaw, any other advice is welcome.

 

Okay i pulled codes today 1st run showed 53 (Throttle position sensor to high), 95 (Thermactor air system problem, 39(Transaxle problem), 13 (RPM out of spec), 32 (EGR sensor or pressure voltage is below closed limit or passed set limit, 33( EGR feedback pressure is not opening), 2( not sure about this one)

turned key off then retested KOEO got 11,11,11,13,32,33,2 (11 means system pass) , did again turned key off and retested and got same codes as 2nd test.

Not sure why 1st test was different then the last 2.

What noW?

 

Are you following your scanners instructions for pulling the KOEO & KOER codes & entering the proper vehicle information intothe scanner?????

The engine should be cold when begining & pulling the KOEO codes, then start the engine & let it fully warm up, without touching the throttle, or turning the AC, or other electrical loads on, or shifting into any gears, before pullng the KOER codes.

If the DPFE sensor is acting up, it could cause the EGR system to act out & cause other troublesome things.

The TPS code suggests the TPS sensor, or it's electrical connections are having problems. If this is so, it'll confuse the computer about where the throttle position is & what to do about it.

So, I'd concentrate on the TPS & DPFE problems & get them right, clear the codes, drive it & scan it agan & see what turns up & post the results.

Just some thoughts for pondering.