pulling my hair out

[cfox101]

Hi, New here. I have a '86 n/a 2.3 Fox stang. Got her with 52k original...1 owner. I always had a slight pulsing idle but car ran well. After doing recent tune up (cap roter plugs wires) I noticed pulsing idle got worse. This started me on the recent adventure.

I have cleaned TB, I have tightened and checked TPS, I had cleaned now replaced IAC, replaced O2 sensor....bought 0bd1 scanner. Got code for bad O2 sensor/lean condition and code for idle set too high (had to set it high because now it was stalling during cold start). After each of these changes I rechecked TPS and reset computer. Changed fuel filter, checked Fuel regulator. Car has 1 year old Coolant sensor I installed (because old one was inoperative) Then I Gave up! took it to someone who guaranteed they would fix it. They called me said it was a bad MAP. Told them to change it. They did , when I got it, I started it and the idle had been reset, was running smooth but I still noticed a slight pulsing idle (again) for about 5 seconds. Asked Mechanic "did you reset computer?" And they said "yeah." I drove away and turned on the radio...noticed my preset stations and clock time where still in memory....DUH! They didnt reset the computer! So I thought well that could be why what they fixed isn't 100%. So I reset computer and have drove it about a week......this is what Im getting now. At cold start, the engine idles up to warming rpms (about 1.5k) for only 3-5 seconds then drops down to regular rpms (around 700) and stalls out. If I feather the throtle it stays running after I manually give it time to warm up. While engine is warming under auto -idle (about 1.5 min) I still get slight pulsing in the idle which then goes away when the Engine is fully warmed. Today I did KOEO got 11-11, KOER gave code 35. Now...is this the EGR itself, the EGR sensor or something else? Code 35 says EGR pressure feedback/regulator circuit...does anyone have any idea where I should look for this considering it is not throwing a normal EGR malfunction code like 31,32,33????

I have spent days on the net trying to solve this problem only exceeded by the hours standing over the engine scratching my head LOL Any help is appreciated. Thanks

[1fast4]

You won't get any help or inserts on here unless you post pics of your sister, tits, our your sisters tits.

Or GTFO

Just the way it goes around here.

[garycrist]

I have had a chunk of "carbon" get hung up on the EGR seat cause this problem. Take the EGR off and check/clean it.

[cfox101]

Thanks Gary...that is what I am looking at (EGR)

[TENGRAM]

...Asked Mechanic "did you reset computer?" And they said "yeah." I drove away and turned on the radio...noticed my preset stations and clock time where still in memory....DUH! They didnt reset the computer!

You can actually reset the ECM by initiating the self-test and then disconnecting the tester prematurely. This saves the hassle of resetting radio presets.

So I thought well that could be why what they fixed isn't 100%. So I reset computer and have drove it about a week......this is what Im getting now. At cold start, the engine idles up to warming rpms (about 1.5k) for only 3-5 seconds then drops down to regular rpms (around 700) and stalls out. If I feather the throtle it stays running after I manually give it time to warm up. While engine is warming under auto -idle (about 1.5 min) I still get slight pulsing in the idle which then goes away when the Engine is fully warmed. Today I did KOEO got 11-11, KOER gave code 35. Now...is this the EGR itself, the EGR sensor or something else? Code 35 says EGR pressure feedback/regulator circuit...does anyone have any idea where I should look for this considering it is not throwing a normal EGR malfunction code like 31,32,33????

I have spent days on the net trying to solve this problem only exceeded by the hours standing over the engine scratching my head LOL Any help is appreciated. Thanks

35 - EGR Valve Position/EGR Pressure Feedback EGR Circuit Above Maximum Voltage of 4.81 volts

1. Disconnect the EVP sensor connector. With the ignition ON and the engine OFF, measure the voltage between VREF and SIGRTN terminals of the EVP sensor harness connector. If the voltage is 4vdc-6vdc, the power circuits to the sensor are OK...goto 2.....NOK?...check VREF to battery ground....OK?...SIGRTN wire needs to checked for open condition....NOK?...goto 3.

2. Reconnect the EVP sensor. With the ignition ON and the engine OFF, measure the voltage between EVP sensor terminals EVP and SIG RTN. If the voltage reading is between .25vdc - .67vdc the sensor is okay....goto 4......NOK?...replace EVP sensor.

3. Check VREF voltage at alternate sensor (TPS or BP), sensor disconnected, Ign On, voltage should be between 4vdc-6vdc....OK?...trace EVP VREF wire for open condition in harness....NOK?...rerun KOEO and confirm failure code presence of sensor used for this test.

4. Ign Off, ECM and EVP sensor disconnected, check continuity of the EVP signal wire pin from the sensor connector to pin 27 at the ECM connector, resistance reading should be less/equal to 5 ohms....NOK?...trace EVP signal wire for an open condition and repair.....OK?.....bad ECM.

*the pin numbers shown above may not reflect yours since this diagram is for an 88-91 5.0


Bottom line is, your EGR Valve Position sensor should be indicating a closed valve voltage of 0.25-0.67vdc. Assuming that you haven't somehow attached a direct vacuum source to the valve (rather than the regulated vac source coming from the EGR Vacuum Regulator), you either have a short or a faulty sensor.