High pressure spring in tbi

[brianblanton]

I have put in a 14 psi spring in my fuel pressure regulator. I have also added a fuel pressure guage on the return line. My truck runs ok when it is cold, but when it heats up to operating temperature, it starts to idle a little rough. I was wondering if I should just put the 12 psi spring back in?
Any help would be appreciated.
I have already replaced the wires, rotor cap, iac, etc.

 

[PlayingWithTBI]

I have also added a fuel pressure guage on the return line

Why? The pressure gauge s/b in the infeed/pressure line. The return line shouldn't see hardly any pressure.

I was wondering if I should just put the 12 psi spring back in?

No, I'd look elsewhere like, ICM, pickup coil, ignition coil, cap, rotor, plugs, wires, etc. Put it on a scanner and see what's going on with sensor inputs like, CTS, TPS, O2, MAP, IAC command, etc.

 

[brianblanton]

It is an obd1 computer. I don't see any flashes on the dashboard. I was just wondering. It idles very smoothly, but just drops down by 1 second in rpm's, and then it's fine again.

 

[PlayingWithTBI]

It is an obd1 computer. I don't see any flashes on the dashboard

It may not have the SES light on but it may have codes stored in the ECM. Checking for those with the "paperclip" trick is good but, a scanner is better so you can watch live data. There are multiple scanners or computer programs capable of monitoring and/or data logging OBDI ECMs/PCMs.