[chaos9913]

i have an 88 5.0 it has NO mass air .. when cold it runs good but when it warms up the idle surges and at about half pedal it backfires, but if i put it on the floor it gets up and moves...PLEASE HELP oh yeah timing is at 10 new cap rotor plugs and wires ...new fuel pump and filter..no mods all stock

[StangLX93]

check your engine coolant sensor, are you getting a Check engine light.

[chaos9913]

how do i check it or should i just replace it...no check engine lihgt

[chaos9913]

changed the temp sensor on the intake and warmed up the car...still the same ....idles fine for 2min then starts surging then fine again .. went around block and at half throttle it pops for a second then picks up and moves ...any other ideas

[chaos9913]

so after the temp sensor didnt work i went back threw my plugs and wires still nothing anyone ???

[89coupe]

DIY KOEO/KOER/Cylinder Balance Self-Test Procedure

Post up what you find.

[chaos9913]

ok got the codes
koeo: 54,32/54,32
koer: 42,92/42/92

[89coupe]

Looks like you have an open in the ACT sensor wiring. Check your connections at the sensor, and clean the 10 pin connections behind the intake. Clear the codes and then rerun them. The ACT may be contributing to codes 92 and 42, which are 02 rich codes.

[chaos9913]

replaced the ACT cleared codes now i get
koeo: 11/11
koer: still 42/92
you think maybe its the fuel pressure regulator on the fuel rail??

[chaos9913]

and the idle still surges when the car is warm.....smooth for about 2min then it will surge for 20 sec then smooth again

[89coupe]

Do you have a fuel pressure gauge installed?

[chaos9913]

i went ahead and replaced the fuel pressure reg.. and for the hell of it all the vacuum lines and pcv valve ...the car idles perfect and all the power is back no more popping ..gonna check the codes ill post what i find