You could put a fuel pressure gauge on it and strap it to your windshield to monitor fuel pressure if you think that is a concern.

Have you cleaned the throttle body, specifically the IAC valve? You could also back probe the TPS (throttle position sensor) and measure the output voltage. It should return ~0.5V at idle and ~4.5V at wide open throttle.

 

Wich wire do I probe to looke for that voltage? I have cleaned the throttle body but not the IAC but I will try tht. I must say that every time I clean the throttle body it feels really good like throttle respense and everything for a couple of days, then its back to its usual self. Its really weird. But when I first cleaned it it was really really bad, and the reason why I did was because the throttle was getting stuck. When I take out the IAC is there somthing I have to do when reinstalling it?

 

Just disconnect the battery for about 10 minutes to get the ECU to reset idle setting.

As far as the TPS sensor goes, off the top of my head, I can't remember which wire it is. I think it is the middle one, but I'm not sure. Basically, you will have a ground, +5V reference, and then the sensor return. You can check for continuity to ground and for the +5V reference wire with the connector unplugged and the key-on/engine-off. Once you have identified them, the last wire will be the sensor return to the ECU. That is the one you need to back probe so that you can monitor it with the plug connected to the TPS sensor.

 

I will do this test and get back to you. Also once warmed up the truck idles just under 700rpm, is this too low?

 

It doesn't sound low, but your idle is affected when you are backing up and braking, correct? Just some things to check to rule out.

 

well I did the test on the tps and I think thats my problem. It fluctuates between .2 and .64 back and forth. Im guessing that means its no good and thats why I am idleing all screwed up.

 

.2 is quite low. What does it read at wide open throttle? Is the progression up through from closed throttle to WOT smooth in terms of the voltage output (ie. no drop outs)?

 

I just cant beleive its been through like 5 local shops no one could figure that out, its like a 2 second test. I am going to get a new sensor and then going to be installing it. Is there a certain way to install these?

 

I am not sure that this is the cause of your problems, but if it is out of spec, it is out of spec.

What were the other readings I asked about? You need to check out the entire range of the sensor before determining that it is bad.

If it is reading low at WOT as well, you could attempt to adjust your TPS sensor. You may have to modify it a bit to get more slop on the mounting bolts though.

 

some areas it just drops ut and there is no voltage. If i hold the throttle say at half it fluctuates up and down, so weird. At idle once i get the engine ho and shut it off I got .1 all the way up to .8 at idle. Shouldn't it be steady?