10/21/2017
Hi, I am new to this and trying to get a grip on it. Sons 1998 Pontiac Transport has been acting up for a time now but has gotten worst to the point can’t trust it to get him or the kids anywhere. So we tried to tackle it this weekend. Went and got the codes. P0102, P0300, P0440. I talked to friend who is out of state right now and said focus on the MAF. So spend the whole night reading and watching info on the internet. And felt we had enough info to make a judgement call on this. So this van will start fine when cold or sitting for a couple hrs. but gets warm and start acting like it going to stall, have to keep foot on peddle and raise rpms. If it stalls very hard to start, need to push throttle down to help it catch and then smell gas as it starts and hear it missing. We have a three wire connector on the MAF. We id the Hot 12v, the ground, the Signal. We get 12 volts between the hot and earth ground when key is turned on. Signal to ground has a very small floating voltage around. when started the voltage on signal to ground is 4.45 volts. and the rpms make very tiny change if any at all. So based on that my friend out of state said it more likely the MAF. $85.00 later we are in the same boat. What did we do wrong? Is this a temp sensor saying it cold and bring more fuel when it hot?

Thanks for any help you can give.

When the van is giving you trouble, can you unplug the MAF to see what affect it has on how it behaves? Does it get better or worse?

Also, when the van is warm, pull the vacuum line off of the fuel pressure regulator. Does fuel come out of it?

Have you checked the catalytic converter at all to see if it is plugged up or broken inside?

We did do the running and disconnect the old MAF and it still ran the same. Son will be here after work to pick up kids and will check the new MAF other two things you mention then. Thank you for your reply