BIG problems since I bought it

[androtaker]

97 4 runner
manual transmission
4wd
diffs
sr5
3.4 liter

I have had my 4 runner for nearly 1 and a half years and I still havent been able to locate the reason for my problems

1: STARTING PROBLEM If the truck sits over (im guessing) 1 to 2 hours then it has problems starting. the engine cranks and everything but I have to sit there and keep cranking on it until it finally starts. once it starts its a little sluggish for about 1 second then the idle smooths out. I have changed batteries alternator, fuel filter and checked to see if fuel pressure was holding after shutdown (it still had enough pressure after sitting for 2 days to squirt out the shrader valve when depressed)

2: IDLE when warming up and after long drives my idle gets very high itll get to nearly 2000rpm and sit there until i hit the gas hard and let off the pedal really quick then it jumps back down. ( I have taken apart and cleaned the throttle body)

3. clunking when coming to a stop (or rolling to a stop without brakes) I get a clunking sound coming fom underneath the truck I can feel it in the shifter and also on the steering wheel.

4. Chattering if I go over 70 the trucks starts to shake very rapidly and loudly (may be the tires) but I dont think so

 

[shoes]

This is just a guess, and I am by no means an accomplished mechanic, but the starting problem, and maybe the idling problem, could have something to do with the choke. My son's Subaru Impreza acted the same way until we figured it out. It would crank and crank, and finally start to fire, then die. Eventually, it would catch and stay running. The problem turned out to be ther thermo-sensor on the intake manifold. It was telling the engine that it was warm when really the engine was stone cold.

 

[androtaker]

hmm, well the only thing that doesnt make sense about that is, when its really hot outside it still wont start, and I think it takes even longer, itll start right up soemtimes when its really cold outside, but its every now and again. definitially something to look into. Ill have to pull the sensor and check the ohmage.


anyone else have soem suggestions

 

[kregg]

mass air flow sensor/ air filter? small things, don't know if you have checked them yet,
as for idle prob, check your throttle position sensor...

 

[Just_Me69]

Clean the throttle body. Carbon build up is the reason for your high idle. After that, remove your idle air control motor and clean the ports on both sides of the throttle body. Good luck.

 

[androtaker]

thanks, Ill take the throttle body off and clean it good. anyone know how to test the throttle position sensor, is there certian resistance at different positions?

 

[Finelygotone]

If this is anything like my (choke, sorry) Ford, the TPS can be checked with KOEO (Key on, engine off). Probe the right wire (no guess on this one) and you should get a range of voltages (low to high) from closed to open, very smooth in transition (no jumping around up or down). Ford's runs (1988 Tbird Turbocoupe) from .96 to about 4.6 volts. The two most important parts about this are the idle (closed) voltages and the smooth increase upon opening. If it does "jump" around then it is probably bad. Also, on my Tbird, I had the same problem with idle sticking at 2000 - a new TPS cured it. Good luck....

 

[BlackFive]

The driveshaft can clunk when braking to a stop or when brakes are released, if driveshaft spline has not been greased in the last several oil changes. Many use Valvoline's synthetic moly for all the fittings.