Hard to start, then runs poorly first couple miles and presto! All is right

[1993rangerxl]

Got a new car so the ranger sits now for a few days or a week. Trying to start requires turning the key off and try again oh 8 to 10 times, finally starts and feels like only 2 or 3 cylinders are firing. Force it down the road couple of miles feels like a big miss fire and then runs great. Any ideas? Thanks in advance.

 

[RonD]

Could be a few things.

You could have a slow fuel pressure leak, wouldn't even be noticed if driven daily.
Next time it sits for a few days, turn key on, count to 3 and turn key off, repeat two more times, then try to start engine.
Each time key is turned on fuel pump runs for 2 seconds, that should add 10-15psi, 1993 system needs 30-40psi

Next would be to install a new ECT(engine coolant temp) sensor, these run about $6-$10
ECT sensor tells the computer the coolant/engine temp at startup, a cold engine needs richer fuel mix and higher idle to run, if ECT is reporting a higher temp that actual temp then engine wouldn't run well until it warmed up a bit.
You don't mention what engine you have?

The ECT sensor will have TWO WIRES connected.
There is also a temp SENDER for the dash board gauge, this doesn't effect engine performance, it only has one wire connected.

 

[1993rangerxl]

I've thought about loosing fuel pressure as a possibility. Has a 2.3 in it. Always runs cold even with Fla Temps. About 100 on fuel pump, now has radiator for a 4.0l in it.

 

[RonD]

Could be someone put in wrong thermostat, should be a 192 or 195degF thermostat.

Size of radiator doesn't matter for underheating if thermostat is working, radiators are for extra heat cooling if needed, so engine should get up to 195degF before upper rad hose even starts to get warm.
Feel upper rad hose before cold start and then after about 3 minutes of idling or driving, should be same temp as when engine was cold, if it is warming up then thermostat is open and needs to be replaced.

Temp sender on the 2.3l is on drivers side rear of engine, just below the head, oil pressure sender is just above it on the head.

Because of this location the gauge will often show just above 1/4 when fully warmed up, most temp senders are located near the thermostat so show max temp of thermostat, just below 1/2 on Ford gauges, about 190degF

 

[naford]

I had a similar problem. I had to mash the gas pedal to get it to start. then I had to pedal the gas to keep it running without hitting the rev limiter. After a few minutes it ran normal and I was able to drive off. I hooked up to the OBDII and didn't see a code. I took it to the dealer and they replaced the idle sensor, plus gave me the obligatory upper intake cleaning. Ran great afterwards.