What does this sound like...

[Phatboy]

OK, so Im having a problem with my car that has several things to notice. I need your help figuring this out. I wont say what I think the problem is until you guys post.

Problems:

1. Poor idle sometimes:

Some times it idles rock solid around 850 rpm or so and is smooth as silk (usually with the AC on). Sometimes the idle is steady at 850 or so, but rough almost like its laboring to keep the idle there. I can feel a slight miss when its doing this.

Some times it starts fluctuating up and down in RPM, once it starts this the range of the fluctuation gets increasingly greater until it dies. Like this 850>950>800>1000>750>1100>600>1200>500>dies

2. Temp gauge is wild:

Running 75-80mph with the AC off it reads on the O, turn on the AC maintaining speed and the temp comes up to the M/A, leave AC on and the car at idle in 90* weather and it reads on the L. I know the stock gauge sucks but this seems like a huge sweep in range even for the stock crap.

Also if I am cruising at 55mph and the temp is on the R, when I shift down and go WOT to pass someone then shift up...by the time I am back in my lane (3-5 seconds), the temp gauge has risen from the R to the A/L area. That seems fast to me.

3. F@#$%% detonation. I know adder will say the stock tune blows goats (and I agree with him) , but with the other issues it seems like this may be linked to a problem. I cannot run 87 octane at all. 93 octane still has detonation at WOT, even with AC off.

Now that I have told you whats wrong...I will tell you what I have done.

1. New parts: Some of these were changed due to other issues.

TFI module x2, the reman unit I got to fix it the first time failed, and Im on the 3rd one now.
Dist,
Cap,
Rotor,
Plug wires,
Plugs (motorcraft gapped at .050),
Harmonic balancer (Timing is dead nuts on 10*),
Coil (cheap master pro, gonna switch it for an MSD tomorrow cause the car is breaking up at WOT and high RPM)
Battery
Alternator

2. Maintenance:

Cleaned Maf, took it apart and swabbed the resistors with Maf cleaner
Cleaned the throttle body
Cleaned the TPS
Cleaned the ITS
New fuel filter...twice
Oil changed and checked level

3. Notes:

EGR and SMOG have been removed, and I am not throwing any codes cause I plugged the EGR plunger 1/2 way.
I have NOT checked fuel pressure as I cannot find a gauge around here, my OCD and scientific brain wont allow me to use an OIL pressure gauge because of the viscosity difference.
I have 17-18inmg in vacuum at idle, and it fluctuates with the RPM surging sometimes.

Thanks for any help you guys give, and I appreciate it!

Sorry for the book!

 

[toyman]

How about the HB has started to crap out and the 10* really isn't 10* but rather 15*. If it's the original HB that's a very likely scenario.

 

[Phatboy]

How about the HB has started to crap out and the 10* really isn't 10* but rather 15*. If it's the original HB that's a very likely scenario.

I personally replaced the HB with a new unit less than 3 months ago.

 

[toyman]

Okay. I don't see where you have either cleaned or replaced the IAC (Idle Air Control) valve unless you are calling it the ITS?

 

[Phatboy]

ITS = intake temp sensor

I have cleaned the IAC valve.

 

[ttocs]

Mine seems to do that 2x a year and almost with out a doubt when it does I can stick my head under the hood and find a spark plug wire that is not making contact and I can see it hanging/wiggling while the motor idles. Sometimes it makes a good connection and sometimes it doesn't.

 

[toyman]

ITS = intake temp sensor

I have cleaned the IAC valve.

It's usually called an IAT (Intake Air Temperature) sensor. Also sometimes an ACT (Air Charge Temperature) sensor. First time for an ITS.