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1996 Toyota Tacoma Hot Weather Starting Problem

I have a 1996 Toy. Tacoma, 2 whl, 2.4L - 4 cycl. Problem: occurs in hot weather only, after I drive a bit, if I stop for say 5-15 min. the car is very difficult to start. I have to engage the starter for at least 15-20 seconds before it will start. When it starts, it does so very gradually. If it sits for 1 hour it will start no problem. My mechanic doesn’t know what’s wrong - HELP!

Try the following test. When you know the engine will be hard to start do a flood clearing, i.e. throttle pedal to the floor while cranking. If the engine catches quicker, either fuel is leaking into the intake manifold in the 5-15 minutes of rest or the computer is commanding a cold engine start when the engine does not need it. How is the gas mileage when it is on the highway?

Get back to us with the results.

Hi, thanks for responding to my posting. Actually, stepping on the gas has a very negative effect - it won’t start at all. To get it to start when hot outside (this never happens when the ambient temp. is under 80F) I have to engage the starter for some time (15-20 seconds which seems like a long time) until it eventually catches. When it starts it does so very gradually (hard to explain … I can tell that the motor is trying to start, but it starts slowly, then normal - if I step on the gas too early it seems to stop it from starting). Since this problem doesn’t happen during colder weather, my thought was that it wasn’t a fuel leak. Your second opinion was that it could be that the computer is commanding a “cold start.” What sensor(s) should I consider replacing to fix this problem?

Sorry, I forgot to answer your mileage question. The gas mileage is pretty good. I just drove it about 200 miles (hwy) yesterday and got about 24 mpg - which is has been normal for some time.

I have the exact same truck that does the exact same thing, except mine will not start without leaving it for at least 30 minutes. I’ve got new air filter, plugs, wires, tried a new coil, cleaned the MAF sensor, tried resetting the gas cap nothing seems to work. Very fustrating, hope someone has a solution out there for these trucks.

I too have exactly the same problem with my 96 tacoma. Here’s what I’ve done so far: New starter, new battery, fuel pressure checks out fine, fixed hole in vacuum hose, complete overhaul of all injectors. What I’ve found is that if I crank on the starter and press gas pedal to floor and let off and repeat procedure until engine bucks around and acts like it wants to start, turn off key and slowly count to 10 and it usually starts fine.

$1100 later and mechanic still stumped. Someone PLEASE HELP!

Solution Found !
I replaced the fuel pressure regulator. Problem seems to be fixed.

Excellent! Keep us posted and let us know if the symptoms seem to come back.

This seems to be a very common problem with lots of answers, but none seemed to work for me. The thing that absolutely cured the problem was replacing an inexpensive but very hard to change out water temperature sensor on the back of the head on the engine. It took me about 2 hours to finally do it but was WELL worth it. These sensors get scorched and burned with time, start working sporadically, then finally not at all. I took my old sensor apart and it was fried inside. Try it, you’ll like it…

Well I spoke too soon. Worked fine for a couple days but went back to its old ways. Took it to another shop and they thought they knew the problem and cleaned the EGR valve and replaced a shot rotor and put in new plugs and did something with a Vacuum switching valve. Still acting up!!! What really honks me off is that these places act like they know exactly what it is and they obviously have no idea. Are there any real mechanics out there any more? I think I’ll try the water temperature sensor thing from spaulding1 below.

Are there service manuals out there or some kind of documentation that can tell me how to fix a water temperature sensor? I’m not sure what a water temperature sensor looks like. Any suggestions?

It looks like a little pipe plug deal with an electrical connector on the end. I’ve looked in my parts store repair manual for the truck and I don’t see any diagnostic readings you can check the sensor against. I hate to just replace it without verifying it is bad or malfunctioning when the truck is acting up. Anyone have a way to check the sensor?

Hi All,

I did a search for “1996 Toyota Tacoma Hot Start Problem” and came to this discussion. My Tacoma would not start after sitting for 10-15 minutes. If I let it “Cool down” an additional 10-20 minutes it would start up like nothing had ever happened. I disconnected the 2 wire connector to the sensor? on the air filter box.
Started up no problem, reconnected - would not start. I left it disconnected and (Aside from the “Check Engine” indicator staying on) its running normally. I do not know what the “senor” is for, but I’ll be heading to the dealer to buy a replacement. Hope this helps… By the way the weather has been warm to hot (80’s -90 degrees)here in SoCal.

The item you’re referring to is called the air filter barometric pressure sensor and the other thing aforementioned is called the coolant temperature sensor, or at least that’s what the guy at AutoZone calls them. Supposedly they work “hand-in-hand” on startup. The bottom line is that the air filter sensor thing is easy to replace and costs around $50. The coolant temp sensor is a bit harder to fix but only costs around $25. It’s getting cooler here in Indiana now so its getting harder to replicate the problem. Will probably have to wait till next summer to see if its really fixed or not. Would be interested to know if the air filter sensor worked though. Let us know.

I took the AIT sensor out and threw it in the freezer for 2 minutes last time the truck was acting up. It fired right up, but also threw a throuble code…maybe too long in the icebox. Makes me think the AIT may be the culprit here, but fall has come and the truck rarely acts up now.

Hi All,

Well it's still warm-hot (70-90+ degrees)here in SoCal. I replaced the air filter barometric pressure sensor. My Tacoma is runnin' fine. I hope this helps..Good luck.

I have looked, not able to find the coolant temperature sensor, found the temp sensor for the temp gauge, but not able to find the two prong sensor. Any ideas?

I couldn’t find the coolant temp sensor either. Must be well hidden. Further developments on my vehicle show the problem somewhere in the airfilter temp sensor. When truck doesn’t start, I pull the sensor out and it starts fine. Truck doesn’t run well without the sensor so I have to put in back in and start the truck again. Pain in the butt but I have toyota dealership working on it. Seems like I’m starting to isolate things. Will let you know what/when/if problem is fixed.

Its a little thing that sticks out the side of your air filter box. Its on the left side and pulls out with some gentle persuassion and wiggle around a bit. It looks kind of like a spark plug but is black plastic. A small tab is held down while pulling the part off.

Where is the filter Barometric Pressure Sensor located? I have a 1995 Tacoma with a V6. What about the coolant temp. sensor?

I cna’t find either of them.