I just got a 89 305 tpi A4 formula as a project car. The problem I am having is it wount idle. When I start it up it idles ok at 800rpm for a second then drops down to about 300 then reves up to 1000rpm and goes back and forth till it dies. When I am driving it. It goes fine if its above 2000rpm. And at WOT it doesn't heasitate at all, has plenty of power. I was thinking maybe MAF, TPS, or Map it seems like its searching for the right A/F ratio. Anybody out there ever have this proublem? Any suggestions?

Thanks for any help

Joe

 

Mine did something similar but it was the TPS. Is the service engine light on or on occasionally? Remeber you can use a paperclip in the 3rg gens to get the check engine light to flash you the codes. I'll post the instructions just in case you have not seen this. http://www.yjshadow.com/ALDL_codes.htm

 

Check for a vacumm leak.

 

Mine does this occasionally and it will idle rough for about a minute and the SES light will come on then it will die.... but the second time i start it up it works fine.. never been able to figure out what it was

 

Thanks for the tip 1987IROC350. Its not throwing any codes, no SES. It costantly goes from 300-1000rpm warm or cold. I think it may be the egr valve stuck open. But I will check for vacuum leakes.

Thanks for the replies

 

Have the original injectors ever been replaced?

 

try replacing the throttle body gasket