Hiccup problem

donatishane · Post by **donatishane** » 15 Aug 2020, 00:00

So I’ve had this problem recently . I installed the ipd hd tcv, as well as a short ram intake from ipd, and turned the wastegate up a bit , and ever since these mods , I have had a problem where under heavy acceleration, the car stutters every 10 mph or so. It slows me down a lot , and almost feels like I let off the gas momentarily . I have tried everything from switching to the stock tcv, and turning the wastegate down , to no avail. I unplugged my maf sensor , and the problem stopped when I drove without it connected . Any suggestions ? Could this mean my maf sensor is bad , or anything else ? I will attach a video of it happening

Cookeh · Post by **Cookeh** » 15 Aug 2020, 04:01

Improvement in running with MAF disconnected does typically mean the MAF is faulty. It is easy to access and clean, so worth doing. I would also recommend checking your vacuum lines as this can cause similar problems - especially as you've recently had them unplugged.

For MAF cleaning, use a dedicated product as stuff like brake cleaner, egr cleaner, electrical cleaners etc can leave a residue which will affect readings.

Post by **abscate** » 15 Aug 2020, 05:21

Your 99 has feedback on the absolute boost pressure inthe intake, so playing with the wastegate will not have the effect that it would on a -1998. I’ve read that more than a turn on a 1999 gets into danger territory, I have no experience there. A vacuum leak will give poor running under MAF CONTROL, which magically gets better without the MAF, as the car defaults to a lookup table based on rpm.

Post by **FlyingVolvo** » 15 Aug 2020, 10:08

You should also get a boost gauge if you're gonna be messing with things, easier to see what's going on with turbo. You should try cleaning the MAF as suggested, though I'm a bit surprised it ran fine under WOT with no MAF plugged in.

donatishane · Post by **donatishane** » 15 Aug 2020, 14:28

Thank you all, any chance it’s a problem with the new tcv? Threw the old one away

Azik09 · Post by **Azik09** » 17 Aug 2020, 02:25

It's overboost. When ECU can not reduce boost pressure via tcv, it cutting off injectors briefly to prevent engine from damage. Feels like ignition is turning off and back for a moment. Very fun when overtaking someone close to another car on opposite lane.