86 2.9 manual trans - bogs when accelerating from cold, erratic idle

[beerhunter]

Hi
Can I please ask for cxome advice. The truck is exhibiting the symptoms in the title. The problem goes away (or decreases to an acceptable level) when up to temperature, but still shows erratic idle. It idles 1000 rmp when warm.

I replaced the o ring beneath the fuel pressure regulator which seems to have helped a bit, although this may be my imagination. The old one looked a bit frayed.

I have since got a pressure gauge and it shows a steady 28 psi, which seems a little low, but not disastrously. No CEL.

I can't see any fuel leaks and sprayed carb cleaner around the manifold, and didn't detect any compression leaks.

I pulled the vacuum hose from the back of the pressure regulator - no leaks. Can the regulator still be bad? Is there a way I can test? I would rather establish a smoking gun than throw parts blindly.

I have one on order anyway, but it comes with a piece of flexible fuel line instead of the fiddly Ford fitting. Will a hose clamp be sufficient to contain the pressure? I don't want it popping off and leaking fuel?

Thanks

 

[beerhunter]

UPDATE: OBD code reader arrived - no codes. Whatsoever. I appreciate these are pretty simple (attach it, press on, press "read code") but am I still managing to screw it up?

If there were a fault/problem when interfacing with the car, would that itself generate a message?

I checked again for vacuum leaks - nothing. I pulled off the air intake hose and gave the throttle body a good dose of cleaner. I then restarted and it initially ran like cr@p (because of everything I had just splurged in to the engine), but then when on a test drive and it felt a lot peppier (to the point where I had to adjust clutch control, as the car was trying to take off from standing more eagerly - not sure how well I described that).

So can a worn throttle body be an issue on these? I appreciate any mechanical part can wear, but I have never known TBs on relatively simple engines like these to be the villain.

Or have I inadvertently temporarily adjusted the air/fuel ratio (with the carb cleaner) and the truck likes it? Is there a way for an average joe to measure fuel/air ratio without a full emissions diagnostic set-up? And wouldn't lean/rich mix generate an error code?

I will test-drive again later and see where it's at, but your advice and experience is most welcome.

 

[rusty ol ranger]

28psi is a bit low.

It sounds like you got a vacuum leak somewhere.

86 still has an EGR system...that would be the first place id look.

 

[beerhunter]

Thanks, I will investigate the EGR

 

[beerhunter]

Hi,

I gave the throttle body and EGR a good clean, and that got the truck running better than ever - better throttle response. I don;t do enough miles regularly to comment on mpg, but the RPMs were lower at steady highway cruising speed so I assume MPG will be better.

Thanks all for your help.

 

[Terrys87]

There are 2 water temp sensors on the front. Give them a good scrubbing with a brass tooth brush. They get hard water build up on them. Its a freebie fix without throwing parts at it.