Hi all. This is my first post on GenVibe. This forum has been very helpful in the past, Thanks!! I'm the happy second owner of a 2007 vibe(140k miles). I'm running out of ideas on how to fix this issue and I know there are some smart people on here that might be able to help.
Recently I had a P0171 code. I didn't have a chance to have it checked out and within a week or two of regular driving, it would not start. My inital thought was fuel filter or fuel pump. When I did get it started, I took it to a "trusted" mechanic and he told me the intake manifold was cracked. After a day, he called me back and said it was not cracked but that the fuel pump needed to be replaced(and Im the worlds biggest dope for not doing it myself). When I picked up the car, it started fine and seemed to run ok. When I tried to turn it on that evening, it did not start. Later I found out it would start cold but had a hard time starting after being driven. At this point the throttle response was getting worse and worse. There was rough idle and the acceleration was heavily affected. So, either not enough fuel, too much air, or the computer was getting it all wrong and the mixture was off. This is where the adventure begins.
Since my first trip to the mechanic, I used it sparely for short trips and was very careful with the throttle(I'm sure I did not help the lean issue by driving it more).
Since the fuel pump was replaced, I first started with the MAF and cleaned it thoroughly(I unplugged it while running and the car died, so I suspect the MAF sensor is ok). I then began checking hoses, squeezing/clamping and bending them. I took some hoses off completely and inspected them. A few hoses only show a little cracking around the ends(maybe 2-4mm of cracking) but the others were fine. I sprayed many sections of the motor with carb cleaner but no change in RPM or anything to suggest a vacuum leak. So, I changed the intake manifold gasket(the Fen-pro black one) and later I changed it again with the updated orange/red toyota gasket. At this point the car is still not running well, can't accelerate past 15-20mph. After this I changed both O2 sensors and I changed the spark plugs(I read a ton of online forums and some people fixed the issue so I figured for why not try). Still running poorly, I did a vacuum test with a gauge connected to the brake booster line. When starting the car, the needle would come up to green/120 and showed a good motor, but 4 seconds in, it drops about halfway down during rough idle but would struggle to come back up to green/20 on the gauge. It would go back and forth, up and down, mimicking the idle speed. I know this is bad, but I could not determine what is causing the needle to move like this on the gauge. When I give a rev(it bogs down but eventually struggles to rev) the needle drops to 0 like it's supposed to and swings past 20 and settles on 20. I thought maybe exhaust, maybe valves... So I started with exhaust, I took out the upstream sensor to bypass the cat. No change, still running poorly(and now super loud exhaust). Next I did a compression test on the cylinders and each cylinder was at about 180 on the gauge which is good. So the valves should be fine. Now I'm thinking it has to be fuel related. I have not cleaned or tested the fuel injectors. I did do the screwdriver test and all of them are clicking evenly. I'm running out of ideas and worried I could waste more money by changing/cleaning, perhaps breaking, the fuel injectors.
At this point, I could replace the injectors... and I could continue to test hoses, or just start replacing them. Does anyone have a recommendation?
Last edited by BenGenVibe07
on Fri May 25, 2018 6:31 pm, edited 1 time in total.