Surging When Warm A9L Upgrade
 

Hello All! I am working with an 87 gt hatch. all bolt on upgrades..
BBK equal length headers, hi flow (no cat) H-pipe, flowmasters
stock motor, heads etc.... i did the mass air upgrade, and ever since when it is cold it runs like a dream. 10 minutes later, (or when i believe it is warmed up) it runs like balls. I just tuned it up with msd wires, platinum plugs, msd cap and rotor, set timing, and replaced the coolant sensor. nothing seems to solve it. any suggestions? O2 sensors? I was told to pull the pin on the distributor (that you disconnect when you set timing.) Bad Comp? It is the a9l computer. i have even removed the battery.....and then reconnected and ran it. Any help is greatly appreciated

Re: Surging When Warm A9L Upgrade
 

Check for codes.

Also check the TPS voltage.

Re: Surging When Warm A9L Upgrade
 

What is the correct TPS voltage at idle for the A9l comp? I was foolin with that but never did put my voltmeter on it

Re: Surging When Warm A9L Upgrade
 

Your throttle body and/or idle air control could be dirty. Maybe wierd coincidence?

Re: Surging When Warm A9L Upgrade
 

Its either lean or has too much timing at idle.

Re: Surging When Warm A9L Upgrade
 

Mine used to do the same thing and it was the O2 sensors. After they would warm up and kick in the car would surge.

I changed them and it was all good.

Good luck,