Car wont rev past 3k rpms, have to rev to stay on

[Dante923]

Hey, I recently got a 91 Galant VR4 and I just started having problems with it. All the mods were done by original owner and it was kinda thrown together (IC piping has mis matched pipes and cuplings). It has an Apexi SAFC and one thing I noticed when I got it was that it was running rich. It wasnt a problem at first until it started affecting the performace under boost, past 5k rpms it would feel sluggish and the A/F guage would be well into the rich zone (Narrowband, no numbers). I setup an appointment to get it tuned this tuesday with a different ecu the previous owner gave me (mapecu2). I figured that would fix it and It would run ok after that so I didnt mind it much untill two days ago when the shit hit the fan. I was driving it normally and me and my brother in his car were on our way to a festival. He stopped for gas so I pulled in and parked and the car shutoff and it seemed like a bad idle prob, which it has had in the past. The only thing is that in the past it only happened with the A/C on. So I started it again and relized there was a problem because it wouldnt stay on. I started it again and I gave it some gas and it started to sputter so I gave it more gas and it wouldnt go past 3k rpms. The A/F guage was goin crazy in the rich zone. I checked so see if a piping or wiring came lose and nothing was appearant but i knew there was a problem. I got the car home and did some research and found cars with similar problems and concluded that it could be one of four things. 1. Boost leak 2. Bad sensor (ECT, CPS, TPS) 3. Bad gas (gas with water in it or something) 4. Faulty wiring I started off by checking all the piping and nothing poped out and I dont have the means to do an actual boost leak test but it didnt seem like that was the problem. I checked the CEL with an LED and found a code for MAF and ECT. I cleaned the MAF, checked the wiring for it, and replaced the ECT. Didnt fix the problem. I checked most of the wiring and some of it looks questionable but nothing looked like it could be the problem. The only thing I can think of is the gas but I cant really cross the other things off the list because im no mechanic and I have little experience with these cars and im not sure if my checks were thorough enough. I dont know what to do at this point, I may just take it to get a diag or something but i wanted to see if I can save some money and do it myself. I have a limited budget and means of testing things and I was wondering if there is anything specific I can check or something I can do to check something more thoroughly. This problem is very frustrating and Im trying my best to locate the problem but it is hard with limited resources. I dont want to throw money at it and hope it works, I want to find the problem and get it fixed. If you have any idea what the problem can be I am open to knew ideas and will appreciate your thoughts, Thank You.

 

[GSTurbo1]

1) check for vacuum leaks in any fuel regulated system
2) Boost leak test
3) spark plug change
4) check to make sure no wires have come loose on you SAFC system or whatever ecu regulates fuel

I would def do these before getting tuned.

 

[Hydecotsi]

make sure the car has not jumped timing

 

[josh408]

1) check for vacuum leaks in any fuel regulated system
2) Boost leak test
3) spark plug change
4) check to make sure no wires have come loose on you SAFC system or whatever ecu regulates fuel

I would def do these before getting tuned.

Definitely check these, spark plugs are like $10, get NGK BPR7ES, gap them at .028, if that doesn't work, do a boost leak test, you can make a tester with things from a hardware store. Here's a link to a thread with a how to build a boost leak tester video http://www.dsmtuners.com/forums/articles-parts-fabrication/386650-how-build-boost-leak-tester.html

 

[miguelmcv]

I would say, its a tuning problem but a boost leak wouldn't be a bad idea.

 

[Dante923]

I have resolved the problem, it was the safc, i reset it and put a safe tune on it, it runs rich now and theres a idle problem sometimes but it was like that before. Im gonna get it professionally tuned tuesday with a different ecu and that should resolve my problems and let the car run how it should. Thanks everyone