2.8 5spd, 1988. Using fuel, sometimes idles , sometimes not. Seems worse when hot . Can drive on light throttle, but anything else can hesitate and stutter mid rpms. Seems to have power when it can.

Thought I found a vac leak, but still same.
Checked tps now at 0.540 up to 4.27v
Had different fuels in car as others suggested and I agreed could be bad fuel.
Checked fpr, seems ok. Has pressure but I don't have gauge.
Batt voltage 12.4 car off. 14.4 car running.
IAT seems good
O2 is new 3 wire
Just found three on one side loose upper manifold bolts, not sure how that happened ? Got it all tightened down now, will drive car tmrw and see if any different.

Basically I'm guna slowly check everything, any ideas, anything you want me to check please post thanks !
Just got codes 24 vss ? 45 rich exhaust.

 

Here's a thread that may help you with your code 24:

https://www.thirdgen.org/forums/v6/6...-vss-help.html

Just to be clear your car won't idle, can run with light throttle, but stutters and dies if you go any further?

 

I'll have a look at that now thanks. It does idle at 700rpm. But then sometimes it will decide to hunt around and get bogged down.
Code 24's annoying, my Speedo works fine, and I don't know when it sets the code. Is it worth just changing it out ? But I didn't think it would affect mid rpm loads?

 

Well I've been out after tightening the loose top manifold bolts, it did not stutter mid rpm this time. It would not idle however. I guess I'll clean the iac then perform an idle relearn.

Edit : just read some funny posts about idle learn hehe

 

All done ready for testing oh I mean driving to work tmrw lol
The iac and crapy idle got me thinking about checking the pcv tmrw afternoon. Might be worth changing it .

 

Did three trips today 60 miles total, went to park it up for the day and it threw its first code since the idle relearn, doh code 45 rich . driving beter, idling beter. Still not right.
guna check pcv system
Guna go through ignition system
This week
I think the loose manifold bolts were a big problem, not sure how that happened, im guessing now the cars being used things are starting to loosen, i prob should redo the rockers just to be sure too........

 

I would check the MAF sensor, my car would throw all kinds of codes even with sensors purchased new from advance auto parts. Ended up finding a NOS MAF on Ebay and she's been purring for about 3 years now.

 

perhaps it's ready for some new spark plugs if running rich? a basic tune-up might be worth a shot?

 

Not sure which posts you read about idle learn. But the 2.8l engine doesn't require it. Just the '90 - '92 3.1l ECMs.

RBob.

 

Why you say its stuttering, its it just like a shake or misfire, or do you hear popping or backfires out the intake. I had a similar issue when I had my 2.8, under load the car would hesitat e and pop out the intake. Went though a distributor, maf, a few sensors, but the it ended up being the injectors were clogged up. Swapped injectors, and went away immediatly.

 

Thanks guys, I do want to get a spare maf, it's on my list. Haven't had time yet but I've checked the coil, tests good. A very quick ht lead test reveals two higher resistance wires.
tnite I'll get the dizzie cap off and plugs out to check em.
I was going to check the injectors whilst I'm there too.
I think now it's being driven things have loosened up and had a few heat , stress, cycles not surprised it all needs going through.

 

Oops one plug snapped, ☹ , it happened way too easy, shame because actually the plugs don't look bad and they all match . Can't get the rotor off, I'm guna try a pry bar next, it is really carboned up, the cap looks quite worn away, wouldn't say its dead but its prob not far off lol

 

So an 88 plug has no. Ac r42ts.
89 plug has no. Ac r43tsk.

They are both 2.8's right ?

What is the difference between spark plugs ?

 

I chew the rotor off with heavy duty side cutters (for cutting wire). Just keep taking chucks off until it lets go of the distributor shaft. As for a pry bar, there really isn't anything to leverage the bar against.

RBob.

 

Good idea, was thinking of using the upper intake to prize off

 

Had some time today reset valve lash on left bank, checked for any broken bits, lots of oil up there so that's good. Injectors all ohmed the same 12.2 which I was happy with. Managed to get 1/8th turn extra on all LIM bolts. Found two header bolts to nip up. I'll look at the right side next before putting it all back together.

 

Had to take fuel rail and middle intake off to get rockers off, shes all rebuilt now , new cap, rotor, and leads. All nicely tightened up. Running ok, so much better than it was. Still not consistent idling though, might recheck the tps again. But it was drivable and very fun !

 

So currently I have the pcv one side and a vent on the other, now it was running ok before like this, but maybe after use the pcv has decided to work more effectively ?? Who knows but I know its not right so I have some pipe coming to replace the vent on the rocker cover and let the crankcase take in metered air.

 

Fyi, this worked a treat

 

So I have made a new pcv pipe and fitted this so the whole pcv system should be working correctly now.
it wanted to stall on me all the time this morning , I have done lots of reading and found there is a procedure to set minimum air throttle adjustment, I have done this and then redone the tps adjustment.

Bottom line though , the car does not stutter or miss whilst driving ! Thanks for everyone's input.
I think overall there was a multitude of small factors but a basic tuneup and rebuild up top, which wasn't hard or that time consuming really was well worth it.