Hi I have something that has got me stumped. I bought an 88 k1500 with a 305 tbi engine. It wasnt running so I checked it and found that someone got a tune up way wrong. So I got it running. Then put headers on with true dual exhaust, eliminated egr valve. Is was rather noisy from the drivers side valve cover. Pulled cover and found cylinder 3 intake and cylinder 7 exhaust valves way out. Adjusted all valves and put covers back on. Now prior to adjustment it was relatively smooth but a little rough. After adjustment its running as though I put a hp cam in. Very lumpy. Can get timing right on but as soon as I connect est it wont stay running. I check iac and it was stuck so that is now new. The throttle plates were seized when I got the truck so I freed them up and bumped up the idle so plates weren't getting stuck on tbi housing. I'm at a loss. If I give it throttle it smooths out but it stalls as soon as I let off.

 

Did you re-time it after you changed the IAC?

 

Retimed after iac and it made an ever so slight difference. I did check one other thing also. After warm up and I shut it down it still wont stay running. Could it be throttle position sensor?????

 

Sounds like the cam is going flat. Any chance the valve adjustment is too tight, valves can't close, so those two cylinders are dead?

WHY would you eliminate the EGR valve?

 

Sounds like you made them too tight. You mentioned you came across two that needed adjustment, but then you stated that you adjusted all of them. Not questioning your mechanical ability, but they sound too tight from what you are describing. Put a vacuum gauge on the engine, and when it can or is able to idle, see if the gauge is reading low and flickering.

- Rob