1994 4.9 I6 5-speed.
1. Never starts on first crank. Starts on 2nd
2. Idles fine.
3. If I give it too much gas..... bucks, sputters. If I back off the gas to a "sweet spot"........runs fine.
4. If I drive it up to full temp, then stop, turning it off...... will not start again until engine cools down (15-20 mins)

Any thoughts gentlemen?

Thank you.

 

Lotta possibilities, suggest pulling the computer codes to see whether anything has been flagged which may help better direct efforts. O2 sensor would likely be flagged here. Can't remember the year of the transition to current-day OBDII somewheres along in that model year range, if it still has the older OBDI and can't find a code reader, there is a how-to sticky note at the top of the main 87-96 forum page here. Please don't load up the parts cannon and fire away replacing stuff without good cause and reason - gets expensive quick plus run the risk of putting a new-bad part in for an old-good part.

Suggest checking the fuel pressure from the port on the fuel rail, for your I6 looking for something in the 45-60 psi range and remaining relatively stable as you 'give it too much gas' where problems start - if not, may indeed be a fuel filter or maybe the fuel pressure regulator...or something else, at least will have something that ain't right to chase down.

May inspect the fuel rail looking for any signs of damage or non-factory bends, and consistent distance off and away from the engine towards any vapor-lock possibilities.

Had the cold-starting problem on my '89 especially after sitting for more than a day. Never ambitious enough to resolve, worked around by rolling the key to On a couple-three times for the 2-second priming cycles before going on to Start, figured the fuel line was somehow draining from a failed check valve or the like.

A plugged cat generally causes rev limitations, where the engine just won't go above say 2000-2500 RPM, opinion is that any misfirings because of this would be unusual.

 

Check fuel pressure before anything else. Spec is 45-60 psi.Possibilities include the fuel filter or pump.

Keep in mind, the O2 sensor's data is not used during open loop (cold engine) operation which is the first few minutes of operation.. If the problem acts up on a cold start, I think you can rule out the O2 sensor.

You can check for codes but the much additional information isn't available till OBD 2 came about in 1996.