I just bought a 94 F150 today for a steal of a price. Or at least I think so. It's an automatic, 302, 4x4 XLT.






However it has an idle issue. I swung by the closest auto parts dealer so that they could scan for codes. It came up with;
3-37
3-34 ( EVP - EGR did not respond properly during test - EVP )
3-32

They're all codes that deal with the EGR valve and pressure sensor. I've heard that these trucks usually have an idle problem because the rubber hoses drying out and crack allowing extra oxygen in. Are there any diagrams explaining where the pressure sensor hose is?
Has anyone had this problem of a surging idle? Any help would be appreciated.

 

Your truck doesn't have the EGR pressure sensor so don't bother looking for it.

The EVP(EGR Valve Position Sensor) sits right on top of the EGR valve and has a electrical and vacuum line connected. The vacuum line goes around the back of the motor back to the EVR(EGR vacuum regulator) which is the little solenoid at the front of the bracket near the coil, and it's this vacuum line that is most likely causing your codes. Try replacing it with another piece of vacuum line, clear the codes and drive it for a couple days to see if they come back.

 

Thank you for your input. I'll try that and report back.
Any ideas why I smell a strong odor of fuel?

 

Does the truck have dual tanks? There is a common problem where fuel is returned to the other tank while you drive and it will overflow out the filler tube and/or into the evaporative system if the tank becomes full. The fix for this problem is replacement of the in-tank fuel delivery module/s which contains check valves that are supposed to prevent this crossflow.

 

Nope just a single tank, single cab.

 

Where is the fuel odor then, in the engine bay or towards the middle/back of the truck? You're gonna have to start looking for a leak.. could be a rusty tank or leaking fuel filter which is on the frame rail, or maybe the fuel tank vent system is disconnected/broken, it should run to a charcoal canister in the engine bay and then up to the throttlebody via the canister purge valve.

 

I was underneath the truck, spraying the EGR and random hoses with WD-40 looking for a vacuum leak when I noticed that my exhaust was cut off right after the cat. Would this affect my EGR's performance?

I hope this doesn't turn out to be more than something simple, seeing how I only paid $1500 bucks for the truck, but I'd like to get my budget low on this daily driver.

 

Looks like the leak is coming from the front of the actual tank. (Single gas tank)