2.3L ('83-'97) 97 ranger 2.3 idle problems, stalling/bucking

[SirPotato]

I have a 97 2.3 5 speed that I just picked up in a trade deal. I could use some help on suggestions to get it back running right. This is a long write up but I wanted to be thorough for anyone that is willing to help.

Issue:
Cold start-
1. The truck will not idle
2. Truck will not stay running without applying roughly 1/8th of the throttle
3. Truck sputters and is on verge of backfiring after first starting
4. Driving in this condition, the truck will shut off when slowing down for a stop sign
5. When accelerating, the truck feels great above 2k rpm

After warm up-
1. Truck will idle at 1k rpm and slowly die off to sputtering and finally die out
2. Truck will sometimes "buck" and cut out between 1500rpm and 2k rpm. Applying more throttle will stop it from cutting out, letting off throttle completely will also stop this.
3. If I raise the idle to 1250-1500 rpm using the set screw on the throttle body, the engine sounds fine and does not cut out.

What has been done by previous owner:
MAF, IAC, TPS, Plugs/Wires (one side), Coil Packs, Fuel Pump, Fuel Filter

What I have done:
Fuel Pressure Regulator, checked all relays and fuses, checked all vacuum lines for cracks and leaks

After replacing the fuel pressure regulator yesterday, I raised the idle slightly to 1k rpm and drove the truck for 15 minutes with no bucking/jerking at lower rpm. When I parked the truck, I let it idle and the truck slowly died out over a 45 second span.

Trying to start the truck again, it would rev to 2k rpm's and immediately die unless I maintained a minimum 1/8 throttle while starting and slowly released the throttle. Slowly releasing the throttle would cause the truck to idle but again it would slowly stall itself out. If I adjust the idle screw to 1250-1500 rpm the truck would stay running and not cut out once warmed up.

Thanks in advance to anyone willing to read all this and throw some ideas my way.

*Previously owned 2 other 2.3 rangers (93 and 96), never had an issue like this before*

 

[SirPotato]

Update- I purchased a scan tool yesterday and the truck shows two codes.

P0102- The MAF is new but apparently is bad?

The second is for the evap purge valve/solenoid.

I am going to start with trying another maf and update later.

 

[Blmpkn]

Update- I purchased a scan tool yesterday and the truck shows two codes.

P0102- The MAF is new but apparently is bad?

The second is for the evap purge valve/solenoid.

I am going to start with trying another maf and update later.

NEW doesn't necessarily mean GOOD these days, sadly.

Ford's really appreciate genuine motorcraft electrical component's. If a motorcraft part is unavailable, it's best to at least buy the part from the company who produced them for ford.. NTK oxygen sensors for example. I'm unsure who made the MAF.. but if a motorcraft unit isn't available.. it would behoove you to find out who did and purchase theirs. Could always go by a junkyard and see if you can snag one there..

 

[scotts90ranger]

If the scanner you have shows live data, look at the air flow at idle, there should be some... Fuel systems with MAF sensors are really mad about vacuum leaks, they want to know about all the air... when I did the drivers side plugs on my '97 I missed a hose (I think the fuel pressure regulator hose) and it was mad... similar with my '00 Explorer when the PCV hose fell off...

Next thing is check the alignment of the aux pulley on the timing belt, if it's off a tooth they don't appreciate that either since that's what the cam sensor is on...

 

[SirPotato]

Update-

I replaced the MAF and condition did not improve.

Next I hooked up a vacuum gauge and it tested at 7-10 in where a normal engine should be between 15-20 in. I figured it was potentially the intake manifold gasket and purchased a set to replace it.

I just finished reinstalling the intake manifolds and made sure all vacuum connections were sealed properly. I also replaced the drivers side plugs while I was in there.

Starting the truck again it is still stalling out and showing a vacuum leak somewhere. When I hold the throttle at 2k rpm's the vacuum gauge is in the normal range, but at idle it falls again to between 7-10 before dying out.

The truck now shows three codes, MAF voltage low, intake air temp high, and the purge valve code.

All I can figure is left is one of the following-
1.The new Idle air control valve is not operating properly
2. There is something vacuum related downstream of the manifold I have not found yet
3. Cylinder head is bad?
4. Like Scott mentioned, maybe something timing related.

Thanks for the replies so far, there can't be too much else to replace