Issues after front and upper 60K

[OmMEGGA]

94' ATX 178K miles.

All parts ordered from SHOsource so I didn't cheap out on anything.

CPS
Camshaft Position Sensor
Timing Belt
Water pump
Vacuum lines
Front Seals
Plugs and wires
Valve Cover gaskets and plug well seals
Timing tensioner and 2 brand new timing pulleys

She starts nice and quick but once idle goes down it stumbles between 900-500 rpm. It usually jumps between 900-700 though. It will even run perfectly fine for 10-20 sec and it starts to stumble again. Engine does not shake. When driving you can feel lot of hesitation when applying moderate/steady gas.

Car does not feel like lost any power. When you floor it, she jumps nicely and pulls hard. Secondaries open up too ofcourse.

I checked vacuum lines and no leak as far as I see, I've reassembled timing belt 3 times, I have gaped plugs and re checked firing order. All good. Everything is connected as far as wires go. Ground is good too.

What could it be?

DIS module? COIL?

I'm ready to set the car on fire ad run it off of a cliff.

 

[SHOspazz92]

Check your IAC.

 

[Bob Gervais]

If it didn't do this before the 60k stuff, then it's gotta be something that wasn't installed correctly.

I know you looked at all the vacuum lines to check them, but this really sounds like a vacuum leak. Check all lines again, and also the MAF. Make sure the tube clamps are tight, check intake bolts...

 

[rubydist]

Good chance of vacuum leak, based on my experiences. If the idle is too high, the pcm will kick open the iac periodically (every 7 seconds or so) to try to get it to "unstick", but if the issue is not a sticky iac but rather a vacuum leak preventing the iac from accurately controlling idle speed, then this cycling will go on forever.....

 

[OmMEGGA]

alright guys! I'm gonna remove and reinstall intake tomorrow as there is big chance I didn't do it right or some stuff got caught in between :/

 

[kevinspann]

Plug wires routed correctly?

 

[OmMEGGA]

Plug wires routed correctly?

Yes. This is not a misfire issue. The engine is smooth except the hiccups on the idle and hesitation when giving gas. I think it would be a lot more severe if I routed the wires wrong... I double checked them and everything is alright with cables.

Also no CEL

 

[SHOspazz92]

Does it do this? (Idle smooth, then get really rough?)

[YOUTUBE]RIekQYq0H9w[/YOUTUBE]

Turn up the volume to hear what I'm talking about. Also, the knocking/ticking you hear in the video is from the secondaries, don't mind it.

-Sam

 

[OmMEGGA]

Something very similar but as soon as the idle starts to settle. It will do that but not as hard and with more irregular skips. I really do think its the intake not set properly on the gasket. I remember not cleaning the area as I was in a hurry.

 

[SHOspazz92]

Something very similar but as soon as the idle starts to settle. It will do that but not as hard and with more irregular skips. I really do think its the intake not set properly on the gasket. I remember not cleaning the area as I was in a hurry.

That most certainly means a vacuum leak. Mine was a very tiny piece of gasket that wasn't scraped off when I had the intake apart, It created the smallest air gap that didn't allow the new gasket to settle. It was a PIA to find!

-Sam

 

[OmMEGGA]

Ok guys!

This is what I did.

I took out intake and I made sure the gasket sits nicely. After I reassembled everything still same bad idle and hesitation. Today I was digging around guessing what could it be.

I disconnected maf and BAM!!!!! Idle smooth as babys butt. I drove it around and the car and it felt a lot better too.

So is it safe to say MAF is bad?

 

[rubydist]

you could try cleaning it to see if that fixes it. otherwise, replace it.

 

[intimdatr]

Be sure to use MAF specif cleaning spray or you WILL have to buy a new one. But usually if its causing problems its toast. Cleaning it may help but its most likely time for a replacement.

 

[OmMEGGA]

Replaced maf. Didn't help. $80 wasted.

What do I do now? I'm just about to give up and I'm ready to sell the car.

Perhaps bad gas or bad TPS? But why would it idle just fine with MAF unplugged?

 

[intimdatr]

It forces it into open loop.

 

[Rubix]

I ran into a similar problem after a 60k once. I replaced the IAC and the FPR figuring it was them. Who knows, it might have been cause the car ran better. I think the real problem was that I didn't let the car properly relearn idle. Have you reset its idle?

 

[jimtash]

Got any codes? Vacuum leaks should show up as an O2 code.

Check your wiring especially the harness behind the rear head and next to the firewall. Any loose connections will cause all sorts of running issues. What about your alternator? How many volts is your battery getting? Should be over 13 volts otherwise there's not enough juice to run everything properly.

 

[SHOspazz92]

Got any codes? Vacuum leaks should show up as an O2 code.

Check your wiring especially the harness behind the rear head and next to the firewall. Any loose connections will cause all sorts of running issues. What about your alternator? How many volts is your battery getting? Should be over 13 volts otherwise there's not enough juice to run everything properly.

The vacuum leak that I posted showed absolutely no code.

-Sam

 

[jimtash]

The vacuum leak that I posted showed absolutely no code.

-Sam

Sometimes they will and sometimes they won't. OBD 1 is funny like that.

He said he disconnected the MAF and it ran better. Then he replaced the sensor and it reverted back to running like crap. Does he have the correct MAF sensor? These things come on all sorts of flavors even though the housing are all the same.

 

[OmMEGGA]

No check engine light at all. Alternator has less than 100 miles. Putting out 13.8v with max a/c on + Lights @ 105F weather.

I bought the maf from autozone. reman. I pretty sure its the right one. Although it could be faulty (very unlikely). Switching it made no difference. Although the previous owner did home made CAI. The tube was somewhat bend between maf and TB ... I fixed that and it helped a little with the idle (I think) Probably just coincident as the car ran just fine with the same setup for quite some time before 60K.

There could be wiring issue like jimtash said, the wiring did receive few nice pulls and bumps when I worked on the car. Funny thing is my speedo stopped working after the maintenance and I cannot find the loose cable. Pretty sure its the cable that supposed to run from firewall to the tranny.

I also see my temp gauge kind of goes up and down. Before it always stayed 1/4th up. never really in between. I have after market gauges and all of them are working except the temp. which was also just fine before 60K. I did NOT replace thermostat.

I'm really thinking its either wiring or something around the throttle body. TPS?
Also wouldn't the unplugged maf confirm that there is no vacuum leak?

He said he disconnected the MAF and it ran better.

It idled not better but perfectly. Ran better too but I guess it will never drive "good" with unplugged maf. I'm also afraid idle and hesitation could be 2 different things...