1999 pontiac grand am 2.4l. Got this car 2 years ago. Has run good up till I month ago. Felt like transmission slipped twice, 1 mile later at light heard loud rattle under hood and died.
Jumped time
I have:
-Replaced time chain tentioner
-Set back in time.
-Checked valves and springs while it was broke down
-changed plugs, boots, tried a new coil but only on one side
-Cleaned idle air control valve
-tested iac by unplugging while running cold start and warmed up. It did move.
-I have removed cat and replaced with straight pipe (I will fix later this is all I have 4 now!)
-O-2 sensor not plugged in from that
-checked for vacuum leaks

This car has 60,000 on odometer. You can see dash has been tampered with I'm guessing not the original miles. Only thing is under hood, other than oil leaks around a few areas it looks pretty good. No cracked hoses, belts, all wires are in good condition.
Is there a mass air flow sensor on this model and motor? There is not one on this particular car nor a plug for one. Ebay still has them for sale.
I can clearly see a spot on engine block for a EGR valve. Again, no valve or plug. I will try to include Pic.
Got the car running. Starts runs a Little louder at the moment (cat) after about ten seconds idle gets rough and sounds like about to die . When I take cold air intake off there is a loud sucking coming from throttle body . The top to be specific. Put my hand over and sucked in like car wash vacuum. About same power. Runs even rougher at this time. Is this normal ?
Don't have any codes now. Got random misfires and bad front cat system on way home with car. This is why removing cat happened. I'm working on this myself. Laid off bc motorcycle wreck so no job at moment. Can't just throw parts at this. She is all I got for now so emissions are at bottom of the list. Any help would be greatly appreciated.

Re

Yeah it has a MAF and should have an EGR. Did you do all of those repairs or did someone else?

I did them. If you Google maf for this car you will find plenty of them for sale but when I call autozone gave them the year make and model with engine size they got a return of "not applicable for that car."
The EGR valve I can see where it goes but nothing there nor a plug to go into it. I live about 2 miles from an autozone. Big question for now is can I make it there to put on code reader? Biggest concern is sucking from throttle body. Straight down thru butterfly. Strong vacuum suction.

OK, was vehicle running ok until the timing chain problem?

You say it jumped time.....how did you determine this? Was there a lot of slack in the chain?

20 year old car with only 60K on it? With the mileage in question, at minimum, I would have replaced tensioner, shoe, AND chain......Normally I would do the kit(cam gears, crank gear, tensioner, tensioner shoe, guides, and chain)......

It'* imperative that the timing is spot on.......off one tooth, will cause idle problems......when you released the tensioner, did you rotate the engine twice, and then recheck the timing?

I don't believe this engine has a MAF, it uses the MAP....as for an EGR, I think it depends on if you have RPO code RC9.......

If you didn't have secondary ignition problems before this, I would doubt you would have them after doing the chain.....however, those plastic ignition towers, that house the coils, are known for carbon tracking.....

Did you ever check compression after replacing the chain?

One other thing to check on these engines is the fuel pressure regulator....known to leak into the vac line.....

Awesome! This is what I'm looking for.
Yes, it ran fine no problems. When I first got it changed out both coil packs. Nothing since.
A weekend mechanic cam by and by the time he left had broke into the camshaft housing covers looking for a broke or damaged valve or spring. He left me having to take timing chain housing off to get it all back together. Good thing was while in there noticed chain had a lot of slack on right side away from tentioner. Also when rotated to TDC before removing chain, the dowel pin holes in cam gears did not line up perfectly. About a few 1/16 * off. Maby 1/2 inch. When car died I did hear Loud rattling sound. Then would not keep running.
When I replaced tentioner the old one was sticking and felt bad. I'm thinking your right about chain stretching bc when I put old chain back had to fight with the gears to get it on. Dowels went in but not easy had to work them toward each other and when tentioner was applied it released a 1/4 inch out further than old one. Did not know to rotate 2 times and check. Do now.! There is no maf on this car. The egr, I can see where one would be but not there nor a plug. The hole is there uncovered. Will that make a difference?
The hissing sucking sound is normal for this car when cold air box is removed from throttle?
If you think it sounds OK then I'm going to fire her up and run up to autozone to get codes. Don't have a lot of money to put into this so I need to be sure what I'm replacing needs it. If timing is problem then I will get kit. Tower housing was my next move. I will let you know what codes I get. Thank you.

Sorry, and thanks Tech II, I thought they'd added a MAF by then.

Died in way out driveway. About to give up on this thing. Still has misfire and when put in gear wants to stall.

OK, I know this much now. I'm only running on 2 cylinders . I believe 1 and 4. After warming up went one by one unplugging fuel Injectors wires. When 1 and 4 were unplugged car died. 2 and 3 unplugged no change in idle. Unless I had 2 Injectors go out at same time this means a coil pack, or coil tower, or bad ICM correct? Is there a way to be sure which one it is rather than buying tryal and error?

I'd say go with what Tech II was saying above:

One way to check the coils, is swap them, and do your idle test...if the misfire moves, it'* the coil....if it doesn't, chances are it'* the coil housing......

https://www.rockauto.com/en/catalog/...l+housing,7068

Here is some more diagnostics:

https://easyautodiagnostics.com/gm/2...sensor-tests-1