Hello,

Been a lurker, but havent had any luck trying to solve this issue. Thank you for your time I hope we can find a solution, because it seems to be a common problem with a lot of solutions.

I started it one day months ago, the van was running like ****. It stalled and sputtered. I barely made it to work. My dad and I played with the timing and boom it was fixed...

months later, van sat for 2 months. I start it up and it puffs smoke and is running like ****. but once it got running-no problems.
i did an oil and tranny fluid change and this changed.

When starting in the mornings, id start it up and it used to rev very strong on start up but sounded bogged down. let it warm up. It has jumpy acceleration, like power cutting in and out. idles and revs fine in park and nuetral(although recently does not even run well under this condition). As the day goes on the engine performance improves, but as the days pass the symptoms became worse.

Stalling, backfiring, slow and intermittent acceleration. Worse at lower speeds than higher, but can still feel it on highway. wtf

I chase a bunch of rabbit holes. almost buying a new distributor. I decide to try replacing MAP Sensor.

BOOM!
problem solved almost immediately.

It runs beautifully for 2 weeks.

Now its running even worse than before. I am going to try replacing coolant temperature sensor next, but wanted to write a post on here to try and get some better input. This is so frustrating, the van runs so well when it runs well.

Any ideas what could be going on? where to look next?

 

Your symptoms are also typical of a bad TPS or a weak fuel pump.

 

Unplug the O2 sensor, drive it that way for a couple days. Any better?

 

Ehh, the thing is, it improves, so why would later in the day run better than earlier? i did replace fuel filter.. TPS is good guess

 

im gonna give that a try