Ok its a 89 5.0, the smog pump is off and I have Cai,long tube headers, and 3 inch exaust. I have been fighting idle surge and 6mpg.. I look and look but I have been getting lost with all the different advice on the codes. If anyone can give me straight breakdown it would help so much. Thank you.
Here is what I got so far
Code 31, I should replace egr and epv? Is this my surge issue?

Code 52, power steering switch? This should not hurt mpg or surge.

Code 41, can't find real info
Code 21, same story
Code 44, same again

Thanks for any help!

 

21-ect out of range. could be a problem with temp sensor or wiring. how does your gauge read? if it is overcooling, that can throw the computer into loop mode and kill your mpg. or if your computer think's it's overcooling

41- hego indicates system lean. I'm not sure on this one, could be a fouled sensor? have you replaced it? can anyone else confirm a fouled sensor could do this? if the sensor is fouled it could hurt mpg.

code 44 thermactor air injector not functioning... that's your smog pump. you will always have that code without one.

code 31 probably would be the evp and not the whole egr... but if it's intermittent, try clearing the codes after you take care of the other stuff and see if the code hits again after a couple weeks of driving.

I'd consider replacing the o2 sensor, investigate the temp sensor, replace whatever is bat there, and check the AIC, those can cause eratic idle.... but I don't think they'll kill your MPG.

 

Ok a "hego" is a sensor?

Should I try and clean the egr first? Or us that a waste?

What is the aic? And I should replace that hey. And the 02 should be done right away too? I will start with all this

31 came up on running and the long storage, and the the code.

 

The truck has to be warm for the test, some of those can be there if it was cold. You can get rid of the smog pump codes if you had disconnected it right, but those don't matter. The ECT is important, if the truck was warm I would just replace it and/or check the wiring to it. I would check the EGR system before randomly changing those parts, it can cause a lean code too. But if the oxygen sensor is old you will benefit from a new one.

 

Ok here is an update. The shop unhooked the egr when they took the smog stuff off. So it is bolted to intake but no wires or tubes connected. I sucked on nipple and it did seal. So what do I do here? Can I leave it unplugged? Or should I remove it and cap it? The wire plug is present but the shop zipped it down . So I know they did not just forget to plug up...

As for truck being warm. I think it was. It's 30 degree out and I ran it for 10 min. But then it was off for 10 before I checked codes.? I just unhooked the bat to rest and I will try to reread.

I just pulled what I think.is the aic and it does not look to bad. But I will clean as it is off. Truck only has 70k on it.

The aic has a blk **** on the side. What does that do?

So looking at this 31 and 44 could be just the pump delete. 52 just steering, so that only leaves 21 and 41 to be my problem..?

What should I do about 41? I will make sure it is warm and te look for 21..

 

The EGR needs to work.

 

But doesn't the egr hook up to smog pump? I'm lost

 

No.

 

Ok so I cleared the bat, cleaned the aic, and seafomed it! I came back with code 33 and 42. Clearly having a warm motor makes all the diff like you said.. now, where do we start lol.

 

still pulling a hego code, so maybe that'd be good to replace. hego is the o2 sensor.... actually stands for "heated exhaust gas oxygen sensor"

it sounds like what you pulled was the aic. you can test it by unplugging it while the engine is running. if it is functioning the engine should struggle and die. but it is probably ok if it's not throwing a code.


to check the egr, turn the engine on, probe the wire on the right side of the EGR Vacuum solenoid (trace the vacuum tube to it from the egr) then ground that wire. this should activate the solenoid and you should see the egr valve move and you RPMs should change. if that is all good, I'd replace the EVP