My 87 with the LG4 just started bogging when I accelerate it wont go more than 2,000 RPM unless I give it really light throttle. if I put it in neutral it will rev all the way to red line, but in drive it bogs at 2,000. I just did a heater core on it and had the computer out but I checked the connections and everything looked good. I also developed a vacuum leak behind the dash cause it is stuck on defrost. Anybody have any ideas cause I'm stumped?

 

I would go after that vacuum leak first. Either fix it the right way or temporarily plug the line to see if it runs better. you may have multiple leaks throughout the vacuum system. I'd check it all out closely. Once that's done and if it's still running poorly I would then start testing fuel delivery. Replace any fuel filters. Check for fuel leaks. Check fuel pressure. Etc....

 

Well I checked the vacuum leak. I found the supply line under the wiper motor came loose. Hooked it up and now the HVAC modes work, but still bogs. I forgot to mention I did just change the fuel filter so ill check that tomorrow. Thanks

 

Figured id update with the fix in case somebody else has a similar issue. Turned out to be a worn and corroded distributor cap.