HI guy's just after any thoughts or advice.

What I have:

1986 Trans Am
305 SBC
TPI engine

What's wrong:

Slight miss at idle (sort of like a faint puum sound when idling.
The biggest issue is the Surging at and on 2000RPM's. You feel it pull then cuts out, basically faintly cutting in and out when your cursing around 2000RPM

What I have done:

New Injectors
New Distributor Cap and Rotor
New Ignition Coil
New Spark Plug Leads
New Spark Plugs
New Sensor Kit

The only other thing I can think off left to do:

!: I have noticed that there is heaps of air pressure when you take off the fuel cap.
I reed in one magazine that on the TPI systems are not meant to have any pressure in the tank. COULD THIS BE THE CAUSE?

2: The other thing that has been on my mind, is I'm unsure if all the injector wire harness are plugged in to the right injectors. I was told that on the TPI systems they are not linked to one injector so it does not matter, but I can't seem to find out for sure if thats true.

3: The Chip that's currently in there is a Hypertech performance chip. I have a new original one ordered but I'm wondering if the chip can cause this.

Thanks to all that can offer help.

 

Mine ended up being a egr valve or egr solinoid. After replacing them car ran great

 

Thats all been removed from what I can see and tell!

 

I would check the TPS sensor. This is what tells the computer at what position the throttle blades are at in reference to the amount of air coming in and what load is on the engine. A bad TPS could also cause this problem.

The fule injector plugs are not matched to any injector and are only different in which side they are on.

 

Hi, I installled a new TPS with all the other Sensors and still there. Even checked the setting again this weekend. I was thinking about re-adjusting the throttel blades but that would not cause the surging at steady RPM's.

Thanks heaps though for your help, not mean others have.

*Anyone know anything about if it's normal to have air pressure release when you un do the fuel cap.*

 

I had the same problem. To test the TPS, disconnect the TPS and start the engine. The engine should run smooth at about 1700 rpms; if the engine has the capacity to run smooth at any rpm. If it still surges, the TPS is not the problem. Turn off the engine and reconnect the TPS and disconnect the MAF. This is how I found the problem with my surging; it was the MAF. When I disconnected the MAF and started the engine, the engine just ran smoother but had slightly poorer throttle response. It is likely that your new chip will not solve the problem; I tried it and the engine ran better with the strip chip. I would not worry about the air pressure so much. The fuel pressure at the rails is more suspicious.