Rough start & idle, stalling

Got the spare alt on, did the same thing rough start and then threw a code. Cant really scan bc i dont have a scanner and one of my tires is flat so maybe tomorrow i can pull the codes

Same code the dreaded p0300 (random misfire). Also noticed im still overheating after my rad change.

96rivie wrote:

Same code the dreaded p0300 (random misfire). Also noticed im still overheating after my rad change.

Didn't hear that you were overheating. This thread seems to be a compilation of various problems. I would look at the overheating issue first and foremost. Misfires could be a result of some other problem.

What are the circumstances to make it overheat?

matt270avian wrote:

Hey all.
Today and yesterday I just stalled randomly without any warning signs. I'll let yesterday go because I was really low on gas so it could have been a starvation issue. But today I had more than half a tank and it just cut out while I was driving. Both times the oil and battery lights flashed. Fluids and voltage are both good (~14.3 volts when running, ~12.9 when not). The only possible thing that I believe to have caused it is a cheap crappy OBD bluetooth scanner I got. It had the same problem as my old one (flashing lights and stuttering) so I ripped it out.

What I'm thinking:
That OBD scanner
Fuel filter or pump (might both still be original)
Electrical issue (wire grounding out or something)

Might be crank sensor.

Maybe just low on coolant, ill be sure to flush and fill then report back.

96rivie wrote:

Maybe just low on coolant, ill be sure to flush and fill then report back.

I seriously doubt coolant level is related to your issues.

Was overheating on the highway and didnt realize it until my car shut off... Sorry dont think you caught that. Since then rough start and idle. I need help asap if not car is going to shop. I just bought a volt meter if that helps at all but i dont know what to test??

Did you confirm that your leak beneath the coolant elbow and by the exhaust manifolds was from LIM gaskets leaking? What is the condition of your oil and coolant? (check at radiator cap not overflow bottle). Any weird smells with either?

Are you still losing coolant? If so the #1 causes are the plastic coolant elbow as mentioned above, and the OEM plastic LIM gaskets. The collapse internally and coolant can be sucked into the cylinders. Eventually it will get bad enough to hydrolock. New replacement LIM gaskets should be aluminum instead of plastic.

LIM = Lower Intake Manifold - these gaskets we are talking about are the manifold to head gaskets and the leak can't be seen from the outside.

Yea it smells like burnt coolant once it warms up, and a very tiny amount of smoke from rear engine bay. I cant tell where its coming from. Its not from the elbow i have replaced recently, how do i determine if its coming from LIM gasket? Or that its not oil? coming from somewhere else.

If you have smoke from the rear engine bay, theres a good chance its your rear valve cover leaking oil. You should be able to verify this just check or feeling for sluge right under the valve cover. The LIM gaskets pretty much inevitably need to be replaced at some point. My leak was visible before I replaced mine, coolant would collect above the front valve cover gasket. If your LIM gaskets are REALLY bad, it could potentially cause all the rough start, idle and stalling as well. Its not expensive and not the most difficult job. If you have the time it would be worth a shot, imo.

If you want to know if your LIM is leaking, you can try two things:

1) pull the spark plugs and examine the electrodes. If coolant is leaking into the cylinders through the LIM gasket, it will leave a cakey white residue, a corrosive build-up.

2) another way is to send an oil sample to Blackstone Labs. For $25 they will analyze the sample and tell you how much coolant has leached into the oil. They are quite familiar with 3800 engines and know what to look for.

Or, just replace the gasket for $40 and a day of work, call it done.

Sounds like we should start over with that many things replaced.
Are the fans coming on?
Did you 'burp' the air from the thermostat housing?

If you leave the radiator cap open and warm it up from cold (you will spill a _little_ coolant) do you see the coolant start flowing? (wait for it to reach thermostat fully opened). It should move quite a lot of coolant.

Is the lower hose collapsing? When the system is at hot/normal operating temp grab the throttle and hold the engine at 2000 RPM or so, and shine some light on the lower hose. Does it hold it's shape or does it collapse? If it's collapsing it could be cutting off flow.

AA wrote:
Try solving one problem at a time.



...probably the best general advice ever. I know I sometimes overcomplicate, confuse or overspend the issue by tackling too many variables at once in my impatience to solve the problem. Methodical testing and observation can be time consuming, but always produces better results and often helps with future troubleshooting.

LMAO!!! I guess i really do have ADD. Maybe we can start with my overheating issues? So far I have new water pump, thermostat, and radiator. Temp going up to 200, then slowly rises to 240.

Is there a cure for my foamy chocolate milk cancer?

96rivie wrote:

Is there a cure for my foamy chocolate milk cancer?

Probably the lower intake gaskets. Foamy chocolate milk means oil and antifreeze are mixing. Usually happens around the LIM gaskets. (Lower Intake Manifold). That could be somewhat responsible for the overheating as well.

What about cracked head?

96rivie wrote:

What about cracked head?

Sure it's possible, but not likely. Seriously, like 99% of LIM gaskets fail and coolant and oil leak back and forth around the intake ports. The replacement should be the revised aluminum frame instead of plastic.

Car is cooler now coolant temp is between 180 and 205..It doesnt seem to stay steady, there is still air in the system i think. Still have the random misfire and stumped on that now, maybe vac leak? maybe bad gas? Or would the LIM gasket leak cause a random misfire?

If it is leaking bad enough it could. If you have the chocolate milk looking stuff like you said, antifreeze and oil ARE mixing and you should start there.

96rivie wrote:

Car is cooler now coolant temp is between 180 and 205..It doesnt seem to stay steady,
snip

Coolant temp between 180 and 205 is an easy one - you have a 180 thermostat so that's the coldest it will run, and the fans are turning on at 205, which is the normal fan enable setpoint unless you modified them to turn on earlier. If you leave the A/C on, the fans should run more frequently. Does the coolant temp stay closer to 180 if you are using the A/C?

yea, im guessing its the LIM gasket?? I have bought the gasket set already and it is the aluminum one, just dont have the know how/time/place/tools to do so, hopefully i can get some help from someone this weekend

going to tackle LIM gasket today/tomorrow.. hopefully fixes all problems rough start, idle, power surge, overheating issue. Praying its not a cracked head or something. Dont have a FSM but i think this site is just as good.. wish me luck fellas!

96rivie wrote:

going to tackle LIM gasket today/tomorrow.. hopefully fixes all problems rough start, idle, power surge, overheating issue. Praying its not a cracked head or something. Dont have a FSM but i think this site is just as good.. wish me luck fellas!

Good luck?! Don't forget to buy the coolant elbow that attaches to the LIM under the S/C snout. It'll most definitely break when you take off the LIM. You can find them in the "HELP" section of the auto parts store.

Ive changed that elbow before so ill just pick up another set if I put it together without it breaking  Ive gotten the manifold off and all the old gaskets cleaned down.. then rain of course. Does the gasket go on first and then the end seals?And then put RTV on top? Which end seals do I use? The orange ones that came don't seem to fit, only the gray ones.

rain rain go away, its still pouring here WTF, but at least our lake will rise after being 10ft away from record low. 80 years ago!!

Still SES light. random misfire, LIM gasket was done, not overheating just "hard" start. I have to press the gas pedal. It turns on but loud ticking noise, and oil light is on. Also on the way home, loss alot of power then it died again. Suggestions anyone?

Fresh spark plugs & wires (AC Delco or Packard Delphi) for the misfire.

Oil light? Is this new? Is it the red light or yellow? Check the oil level for sure. If the red light is on, that's telling you the oil pressure is low. You shouldn't run the engine until you know what's causing it.

Plugs and wires are new, The oil light is the red one, it slowly came on after the LIM gasket change. It flashed a couple times then just stayed on.

chasing the misfire\ overheating issue, we have swapped PCM, coils,wires, plugs, Battery, alternator, cleaned MAF, filled with new tank of gas, New thermo, radiator, waterpump, then finally LIM gasket,

The red oil lamp could be a bad sign. Be sure the oil level is full, even if you checked it recently. May want to replace the oil sending unit and wiring, but if it is actually low oil pressure, the engine could need service by a pro. Might be worth the price to take it in and have it inspected.