1999 I30 Chugging and stalling

[truc0011]

I'm trying to help a friend out and thought someone on here might have an answer. I see lots of posts about similar problems but can't find the solution to those problems.

He has a 1999 I30 which was chugging, and stalling with a check engine light on. He brought it to a local garage which told him the MAF was bad (they say the code read as low voltage to the MAF) so they instantly told him the MAF was bad and it needed to be replaced. Well he paid the big bucks to put a new one in and the car does the samething but has no check engine light on. Now the garage says it also needed a knock sensor. I'm thinking the plugs and coils should be looked at first. What does everybody think?
Any help is much appreciated - Thanks!

[Nahkapohjola]

Originally Posted by truc0011

... and the car does the samething but has no check engine light on. Now the garage says it also needed a knock sensor. I'm thinking the plugs and coils should be looked at first. What does everybody think? Any help is much appreciated - Thanks!

Knock sensor doesnt cause stalling (only retards ign timing if broken).

'New' MAF can be dead. If reman is used, maybe (?) the third one works
Its 'five' minute job to swap.

Mileage? Std plugs have to be changed every 5k miles, platinums last 60k. Coilpacks start to die at 100k (fit symptoms).

Degraded signals: Connectors can be oxidized; shops wont ever check em... clic link below. Bad or missing MAF, Rev, TPS -signals cause ECU to drop into safe mode ( =2k rpm ceiling).

Everything starts from checking charge voltage, at batt, at ECU - to ensure healthy pwr supply & grounding.