Hello, I have been having a problem with my 99 Blazer 4x4 for a while now.

When accelerating from a dead or rolling stop, it stutters between the shift from 1st to 2nd. It doesn't always happen, but it's roughly 1/2 to 3/4 of the time. Weather seems to make no difference. It mainly does this from 1-2, but also has happened from 2-3. Also, while driving at freeway speeds (70mph) it will stutter or surge or hesitate. Only at around 65-75 does this become evident. It feels like either the engine is stuttering or something more like the ABS is kicking in.

I'm more inclined to say this is a 4wd issue, but this only happens in 2wd mode.

I recently (Today) changed the fuel pump assembly because that was bad (confirmed by mechanic). I'm not made of money and they wanted 900 dollars to do what I could for a couple hundred and an afternoon. The truck runs SMOOTH and starts right up with no issues. It's just the shifting thing, but it feels less like the trans than it does something else. It tows and hauls just fine. I don't feel a ton of slipping under heavier loads.

The engine has been replaced since I've owned it and so has the plugs, wires, the whole shebang.

I've been harassased by a friend who's raised my concerns of the tires. Uniroyal doesn't make the exact tire for the truck anymore and so I had to get another brand for a flat last year. He told me that I'm tearing up the transfer case, but I thought that was only an AWD problem, not 4WD. I only use the auto-4wd in thick michigan snow anyways, so I'm hoping I'm not doing damage to it. While I cannot recall if this issue took place before the tire change, I'm fairly certain it did.

The engine runs fine with no hesitation when I slightly rev the engine in park. The shifting issue is not violent, but it goes from slight to very noticeable on any given day.

Are there fairly simple fixes to try first before I decide to spend more money on this thing? (Paid 4800 for it and spent 5k on it already. Could have bought a new car by now)

With the current automotive industry the way it is, I have been a victim of the pink slip monster like the other 12% of Michigan. I'm hoping to keep the cost low, but I fear this lemon is going to cost me several more thousand before it's through.

Thanks for any help I may receive!

 

Pull the distributor out and see of the gear on the bottom shows wear. Be sure to follow appropriate instruction for that.

I just replaced the distributor in mine a couple of weeks ago due to similar symptoms. It would stutter and hesitate when it was trying to shift 1-2 and then at highway speeds it would miss. The torque converter also didn't want to lock up at highway speeds. If you put it to the floor it ran great. New distributor took care of all of that.

 

I will try that.

It would make me sad that the mechanic I had give it a tune up would have missed something like this.

Hope it works. Will update when I find out.

Thanks.

 

The Check engine light has been on for a while and I got that checked. The P0442 code popped up when I took it to Autozone. I can't imagine that a faulty gas cap has been making this problem. Could the EVAP canister or vacuum leak cause these issues?

 

P0442 - Evaporative Emission Control System Leak Detected (small leak)

A leak in the EVAP system can cause a hick-up in the motor when the purge solenoid opens.

 

I haven't had the spare time to get under the truck lately, but another symptom I've noticed recently is that when it's about 80 degrees or higher outside, the truck runs smooth with no issues. When it rains or is less than 80 degrees, it runs very poor.

 

I replaced the purge valve in the rear about 2 weeks ago. It's running slightly better. I'm going to try the Purge solenoid in the front fairly soon.

One thing I've noticed now is that once I've been driving for a while, say 20 minutes, the stuttering stops and it runs better.

 

Did you check the distributor gear yet? I had all the same problems that you are describing on my 1997 Jimmy. My code reader showed EVAP problems as well, but I think the stuttering of the engine caused them by not applying a consistent vaccum. Changed a badly worn distributor gear, truck ran like a top, no sign of EVAP issues after that.

Steve

 

the other potential problem that has occured with the distributor on these trucks is that since the reluctor is a press fit onto the the distributor shaft, sometimes they tend to slip which changes the timing and then causing the same exact problems you are describing.....thats why a lot of times after changeing the entire distributor the problem now goes away even though the distributor gear looks ok.....just thought id let you guys in on that little secret....