I have been working on this problem for some time and i am hoping someone can help me with it. I have checked my tps countless times doing full sweeps up and down and it checks out. Here is the problem i am having:

At idle the rps jump from about 700 to 800 and sometimes when i come to a stop it will jump harder and actually pull the car a bit.

Also when i am driving for awhile and i come to a stop the car will not go, has no power and is jerky. If i push through it the car will work it out and go again and may or may not do it next stop.

Now here comes the weirdest part of it all, something i have never seen before. When i get her on the highway and I have reached my cruising speed anywhere from 65-70 the rpm gauge start jumping and you can feel the car jerking. The rps jump alot and my friend thinks it my be electrical, can jump from 1500 rpms to 2000 rpms (this is an example dont know the actual numbers but its close). (Edit) When the rpms start jumping if I increase speed or let off the gas it stops.(end edit)

My gas milage has not been good at all since i bought the car and have worked out many problems. On a full tank of gas driving normal i can get about 180 miles to the tank. Seems bad for only being a 305.

Thanks in advance for any help.
-Buddy-

 

Forgot to add that when I step on the gas from the stop it does hesitate then it will go and you here a little rattling from the car.

-Buddy-

 

im not too sure on this, but your iac valve might be malfunctioning, thats usually the problem with iregular idle... however the iac might be trying to hide another problem by constently adjusting. im not sure if the iac valve is supposed to work only at idle. but if it was on all the time it might be giving u a pulsing feeling on the highway, cept i dont think the iac valve would supply enough airflow to alter rpms at a higher speed, check for vacuum leaks for sure

 

I guess I would suspect the ignition system, namely the ESC, distributor module or grounding connections.
Have you datalogged or checked for error codes?

 

Its not currently showing any codes i got them all cleared after replacing the Maf with the one from advanced with the circuit board, and the relays. I know that sometimes when its cold it will throw a code for a few min but if you turn the car off then on its gone.

-Buddy-

 

I did adjust the iac valve using the tech write up, is there any other way to test if that is the problem?

-Buddy-

 

well the iac valve isnt really adjustable you are essentially adjusting your idle speed not the valve unfortunatly.

 

this might be 2 separate issues. sounds like the highway issue is related to the tc lockup clutch not holding. it grabs, your rpm goes down... it lets go your rpm surges up again.

 

well if youd like to test that you could dissconnect the plug on the side of the transmission, that will stop you tcc from working. might not have back up lights while doing it

 

The rattling sounds like a timing issue, the surging sounds vacuum related. maybe the EGR is stuck open?

 

egr generally causes a rough idle, not usually a surge but it may be worth a shot. unplug it and and plug the vaccum line.
i fabricated a egr block off plate for my car.

 

I went to a local f-body meet and they took a look at my car and told me that its most likely the fuel pressure regulator, so i am going to give that a try. It has a brand new egr in it.

-Buddy-