Intermittent no crank/no start. I've replaced starter, battery, and clutch pedal position switch. When this occurs, I have plenty of power operate horn, headlights, wipers etc. No engine codes stored. Problem occurs after car has been driven for at least 20-30 minutes and then trying to restart. The longer it's driven, the longer it takes to restart. After letting it sit for an hour or two, it fires right up with ease. One temporary fix I've found is that if I swap out the starter relay with another one in the relax box, it will sometimes start. Any ideas?

Mitsubishi Grandis , year not old, no engine size told or VIN.
2003 to 2011 made, sure.
starter failing for any reasons is a simple thing, (unlike bad engines 50 ways to fail)
Battery must be good, load tested, did you know batteries can even be intermittent a hard fact of life, good ,back,weak or intermittent or simple not charged up.
or 10x more often battery lugs loose ,or rusty or BOTH>?>???>
jumper cables ,jump start any dead starter car>?????????
ok Jumps fail so we do what? now.
Your car has an automatic transmission. but some are 5speed manual transmission,s for sure. so I answer 2 times blind, sure
A/Tbox
the PRNDL switch bad for PARK cranking, we shift them all to N
to neutral and crank if this works PRNDL ,P switch is bad
car #2
if M/T tranny, the clutch switch bad kills the starter dead.
no sound means starter motor is dead , the tests are simple
one can have a car battery load tested for free in most shops and vast stores here in USA,did I say FREE, I did.
learn to use jumper cable
learn to start in N
if clutch pedal car, learn to short the 2 clutch pedal top switch wires and the starter motor goes BACK to working again or

if all tests fail we hot wire a starter motor, ask
and if that fails a new starter is replaced. (battery NEG lug pulled first)

What do you mean , tries to start ? When you turn the key to start what happens ? Starter clicks , starter spins the engine around . Doesn't start an run . ,what ? Now it just so happens that your vehicle does not have a relay switch . Does the car have automatic trans . or manual ? Power from the ignition switch goes through the park neutral position switch to the starter solenoid S terminal for auto trans , An through the clutch pedal position switch for a manual trans .

Your best bet , have a qualified repair shop check it out .

I will try to help, powell. Your start circuit from battery to ignition switch to starter-and back to battery. You may need to check every thing here, including the grounds, for a loose connection, or just possibly a failing part.
If only complaint is intermittent starter action, and no other problems with ignition switch, let's assume switch is good, so battery to ignition switch is good. Now from the switch, a yellow start wire goes to the instrument panel fuse block, to "crank" fuse #8 (10 amp), from there a purple wire goes to the safety switch. If manual it is a clutch pedal position switch (simple on/off switch-when clutch down switch is on). If automatic, purple wire goes to Transmission Range Switch on the transm.-in park or neutral the purple wire has continuity in and out of switch.
From that switch, the purple wire goes to the starter relay (under hood fuse-relay center). Now the relay: purple wire in start will energize the relay- wire goes to coil side of relay, and then coil side goes to ground. On relay power side, the power feed is a red wire-and it is the same red wire that initially sends power to the ignition switch. A 40 amp fuse in fuse-relay center sends power to ignition switch, and a splice goes to the starter relay as the power feed for relay. When relay is energized, contacts close, and power is sent from relay to the starter solenoid, again on a purple wire. When solenoid contacts close, starter motor is connected to the big battery cable on the starter.

There is your start circuit. try a new or different relay, try a new or test the clutch switch (or transm. range switch). Buy a $5 test light and use it to check where power is lost when starter won't operate. Hold key in start and check if fuse #8 is getting power. Check the safety switch, with key held in start, the purple wire should be hot. Check if relay has a power feed (pull relay out and check terminals) and if relay coil has a power signal in start. Check the relay's coil side ground. If that ground is intermittent, relay won't work.
When it won't start, use a test light, you should be able to find it.
Good luck.

check for12 volts at starter solenoid when in crank position..

clutch pedal start switch.???

Intermittent electrical problems are the worst to diagnose.
One thing you have not replaced yet is the key switch.
I would run a wire to the starter solenoid terminal that has the wire from the key switch and have a meter ready for the next time it fails to crank.
If you have no voltage on that terminal it may be the key switch. You can also jumper that wire to battery power to see if it will crank by putting power directly to the starter solenoid.
I am assuming the security light is not on when the problem occurs.

So it's a no crank condition? Do dash lights, gauges, and everything else work when the car won't crank over? If so, buy a cheap $5.00 testlight, and when the car won't crank, pull the small black wire off the starter solenoid. While someone holds the key in start (cranking) position and clutch pedal depressed, see if the black wire has power as it should. (Ground the testlight and just touch the wire's end terminal. If powered, the testlight will light up.) If power there, then the starter solenoid is failing. Toyota starters are very good units, but the solenoid's internal contacts get old and pitted.
If no power at the black wire, then the start circuit from ignition switch to clutch safety switch (on the clutch pedal) to starter relay to starter solenoid will have to be diagnosed. To double-check: take a single battery jumper cable and put it on the positive battery post connection. Put the other end of the jumper cable on the solenoid terminal where black wire was removed. Key can be off. Make sure car is in neutral, brake set. If starter now operates, solenoid is O.K., and it is a problem in the start circuit, -ignition switch, neutral start switch, or in the wiring.
Now find a grounding place for testlight under the dash. When car won't crank, check for power coming out of ignition switch on the black wire with white stripe. This is the start wire for the starter solenoid. Key must be in crank position. Wire shoud be powered-ignition switch is working. If no power, switch is failing. You can do the same for the clutch start switch-it's a simple switch, that when clutch is depressed switch is closed and passes power on from ignition switch to the starter relay (thus allowing power to the starter solenoid). Black wire, red stripe-this is wire from clutch switch to starter relay. When key is in crank, clutch depressed, this wire should be hot.
With me so far? Still haven't found a problem, or any loose connections? Next and last is the starter relay. It is located under dash, close to gas pedal, but under the center console, just forward and left of gear shifter. It can be tested and the wiring diagnosed there, but relays are cheap, so just swap in another and see if that helps.
If you have tried everything, and still no help, you could try a new wire from the relay to the starter solenoid. This is that black wire we started with. Older toyotas sometimes have a problem with degraded wiring not passing enough current to operate the starter

if the battery is OK, but the starter still won't crank, there could be a number of possible reasons. Here are some of them:
- The ignition switch could be at fault - it's a common problem.
- The starter motor itself is common to fail.
- Starter motor control wire could have bad connection.
- Cars with an automatic transmission have a Neutral Safety Switch that allows the starter to be operated only when the transmission is in "Park" or "Neutral" position. When this switch isn't functioning properly, or for example, when the shifter is not fully engaged in "Park" or "Neutral" position, the starter also won't crank.
- Similarly, cars with manual transmission have a switch installed at the clutch pedal that only allow the car to be started when the clutch pedal is depressed. The problem with this clutch pedal switch could also prevent the starter from operating
- A problem with vehicle's security system or some other electronic control module (e.g, PCM, BCM) may also prevent the starter from operating.

IF YOU TURN IGNITION SWITCH ON POSITION GET NO DASH LIGHTS RESPONSE.IGNITION SWITCH IS BAD.IF YOU ARE GETTING DASH LIGHTS.YOUR STARTER SOLENOID OR STARTER IS BAD.THE STARTER REAY IS BAD OR FAULTY CLUTCH PEDAL SWITCH FOR MANUAL TRANSMISSION OR TRANSMISSION PARK NEUTRAL SWITCH OR SHIFT SENSOR BAD.THESE ARE THE POSSIBLE CAUSES.

I suspect the starter solenoid,mounted on the starter was 'stuck' on the engaged position.operation in the condition you describe has caused it's failure.starter needs to be replaced.

It is not a clutch slave cyl. or clutch master cyl. problem, first check battery and and cables to rule them out if good check to see with test lamp if you have power to start switch at pedal cluster, [key in crank position] If you have power then check with test lamp, [key in crank position and clutch in] for power at starter solonoid, if no power replace switch at clutch pedal if you have power to the starter then you have a bad starter.