My 1990 chevy k1500 stalls when i turn my headlights or heater fan on .. I have replaced my tps sensor.. Coolant temp sensor and map sensor. But the problem remains and only does it when i run either
Check for vacuum leak. Spray carb cleaner around vacuum lines and listen for idle change. If it does u have a leak. U can also safely plug main vacuum line at booster(BUT DON'T DRIVE LIKE THIS), and see if it doesn't stall. If it doesn't then it indicates leak. These motors are very vacuum sensitive and I had similar issue. Also sea foam through main line is great for cleaning and can helphelp. It has instructions on back ofbottle.
Search Chevrolet C/K 1500 Questions
Are you a UK consumer? CarGurus now has a discussion forum in the UK.
Chevrolet C/K 1500 Experts