82corvette
Well-known member
I pulled the old GMC HD2500 out of the garage last night to wash it up for this weekend trip and it shook & the engine missed for about 10 seconds. I thought maybe after 3 weeks setting idle it just needed a good drive. Wrong! I got out on the street and it shifted from 1st. to 2nd. so hard it about threw me out the back window! I grabbed my Snap On scanner from work and it gave me a code PO 1810 tfp valve switch circuit malfunction, basically the trans or control module doesn't know what gear it is in so t builds a lot of pressure. It only has 49,000 miles and has been flushed every year I couldn't believe a switch was bad in the trans, especially since it idled rough just before this problem popped up. Well long story short I checked plugs and wires, cleaned the injectors and looked for vacuum leaks. I found the map sensor was a little loose in the intake manifold . When I moved it I got a trouble code again, PO 1810. I spent 60 bucks for a new map sensor and the truck is happy again, so am I! Sure beats pulling that tranny out.
