Hey all, I was wandering why my T/A with a TPI 305 is surging at hwy speeds. seems to run fine around town. I have changed the o2 senser, TPS, MTS, cap & rotor, plugs & wires, and cleaned egr valve. the plugs where nice and clean when i changed them so its not running rich or burning oil. the car has gutted cat and looks like oversize 2 into 1 ex. pipe. i have had the car for only a couple of weeks now. I dont have any exp. with TPI so I am a little lost on figuring this out so any help will be greatly appriciated ( where is spell check ) LOL

 

replace your fuel filter, if problem persist check fuel pressure. A surge usually means a lean condition.

 

Surge at cruise can also be caused by clogged purge canister.

 

thanks for the replys, I will change the fuel filter and check the pressure and check out the purge canister

 

Datalogging is a good place to start.
Ditto on keeping and eye on the fuel pressure.

Plugging off the vacuum port for the canister is a quick way to test that.

 

A batter way to eliminate the canister as the cause of surging is to loosen the gas cap and test drive for comparison.

 

not looking to jump into anyones post but I'm having suring at idle and intermittent lean at idle, I have my canister eliminated and the metal line that goes to the gas tank is open. Could this cause a problem with my idle? I wil put a vacum cap over it and see if the idle changes.
https://www.thirdgen.org/forums/tpi/...e-surging.html