Another motor swap done but runs funny

steiner_5000 · Post by **steiner_5000** » Wed Aug 15, 2007 10:31 am

I just got another 4.0 swap done on my B2 and it's running really strange. It'll start up then rev high then chug and almost die unless I touch the gas but then it revs high again then slows down and dies. I'm thinking it's either bad gas or a clogged fuel filter. Both probably need replacing. Any other ideas?

Bob Myers · Post by **Bob Myers** » Sat Aug 18, 2007 6:15 am

Vacuum leak. If we are talking about more than 100 rpms, 'puter is searching for a happy medium of rich/lean and causing the surging.

steiner_5000 · Post by **steiner_5000** » Fri Sep 28, 2007 7:17 am

I went through all the vacuum lines I could find and made sure they were plugged in good so I fairly sure its not a leak. I put a code puller on it and got a 41R code which the book said- HEGO Sensor voltage low/system lean- was the reading I got. The book also said that is an O2 sensor but the sensor I put in is fairly new. Is there a way I can test it to make sure its a sensor?