sounds like a cranksenser.it will put your timing out when your under load .markstang
Not running on all cylinders: Bad spark plug? Bad spark plug wire? Bad valve? blown piston? Do a compression test
Never put Bosch spark plugs into a US engine. Normally they fail. Use Motorcraft--good experience speaking!
the problem will be one or more coils and plugs needs replacing
rings are burned and there is only enough compression to run the engine without load.
When under a load the errors will be shown faster
tach acting crazy on my car too,it would spike up to 6,000 rpms without the engine racing.replace the cranckshaft sensor.
Is this a v6 engine? Does it occur only under load (in gear, wors if you power brake lightly)? If the answer to these questions is yes, it is an ignition fault, probably the wires but check for worn plugs or weak coils also.
If only under load then......spark plug leads.
Overheating? Under load could be a bearing Needs higher octane fuel Timing too far advanced
It might mean that you have a worn serpentine belt. While accelerating, it's under load. While braking, that load decreases. Eyball the belt and look for damage/wear. Replacement is not too terrible a job. FriPilot
Why power generated with under frequency is harmful to the load?Read more: Why_power_generated_with_under_frequency_is_harmful_to_the_load
Yes, the cross member is under the load on a 1989 Chevy van.