Too lean?


New Member
I have an '84. It has KB headers and no cat.

It seems to run lean- you whack the throttle in Park and it hesitates. Throttle response is so-so. If it hard a carb, I would know where to head.

38#'s of fuel pressure, unplugged, at idle.

I don't have thousands invested in scanning tools just to keep it running, but some of you are very knowledgable about these cars and I would appreciate some good advice.

I gave the MAF a couple of whacks. Partly because I read about here, and partly just because.

I can check TPS voltage with a volt meter, if you deem necessary.

Thank you.

What kind of boost are you running, and do you have a fuel pressure reg .

If you do not have a fuel press reg and you are playing with theboost then drop it down some. Take some air away. Mine idles bad because my iac is not set you can check the iac and set it might make it idle better.

Don't fell bad i don't have a scan tool ether.;)
I've not been in the boost, yet. It's my wifes car and it just started to run poorly. I replaced the coil which made a huge difference. At least it starts now.

But it runs too "lean" (or ?) to enjoy driving it. Once it upshifts, it starts to fall on it's face again and this is while driving normal (for me), not a WOT upshift. I'd say power valve, but it doesn't have one!

I'll check the EGR and gasket area. With all the sensors and stuff to make these cars run, if I unplug the EGR can I test it that way? A before and after test.

I've looked for vacuum leaks at the other fittings, none seemed to be apparent.

Any other way to determine air/fuel ratio without scan tools? It has a fresh O2 sensor in it now.

Thanks again.
If you have a good meter you can check it with that. Its been a long time since i did it but i think you ground one side of the meter and hook the other side to the o2sensor wire , you will have to prob the wire. i think the car has to hit a temp or some thing before it can be checked. You also need a meter that go's pretty high.

I think the other guys can help you with this, i'll see if i can find out where i saw this at.
Oh yeah, it has a fuel pressure reg, it seems non-adj. It holds fuel pressure for about 20 minutes after being shutoff.

The car also idles fairly smoothly with 20" vacuum.

However, it won't start without giving it some throttle while cranking. It used to fire with a twist of the key using no throttle.
I think if you set your IAC again and the re set you TPS i think this will fix your idle problem .

Mine does the same thing now and its because i did not set my iac yet. It has a mis if i step on it at idle and when i put it in gear it try's to die on me some times.
I appreciate the advice, but the idle is good. It just doesn't like to have the throttle blade opened. It appears to have a lean condition throughout the whole rpm range, even in Park with no load on it.

If I give it full throttle at an idle, it hesitates, bogs and slowly will rpm. The exact same thing happens while driving it, no matter what speed you punch it at. As it upshifts under normal driving conditions, you have to give it a fair amount of more throttle to compensate for the upshift.

In fact, it needs about 3/4 throttle to keep running if it shifts into 4th around 35mph. Eventually, that 3/4 throttle gets you to about 70mph or more if you held that position for another 30 seconds or more.

Am I making any sense?:rolleyes:

I'll play with the IAC and check / reset the TPS tomorrow, but it seems like the problem lies in the fuel enrichment area, unless the EGR or gasket is the culprit. Unplug the EGR- yes/no?